We met at consultancy LBA’s offices on Borough High Street, on the south bank of the river in Central London, round the corner – not unexpectedly – from London Bridge station. (We shall come to why it is there later.) Bob Ibell is a happily talkative man, full of anecdote, and clearly equally full of passion and enthusiasm for engineering and tunnelling. What got him into it?

“I’m not quite sure,” he says. “I didn’t want to be office bound. I wanted to be out, and doing something positive, something useful. Both my parents were teachers – my father was a headmaster – and they both worked hard, so I had that from an early age. When I was debating my future, my father said, ‘I tell you what, come along and talk to the Borough Engineer and then you can decide whether you want to do that sort of job.’ So that is what got me going along the path.”

It wasn’t quite straightforward: “I messed up my ‘A’ levels, so I nearly ended up as a Quantity Surveyor. But at the last minute I got accepted into Aberdeen University, to do Civil Engineering.

“I didn’t stay for an Honours, (in Scottish Universities that is a 4-year course) because I was keen to get to work and Taylor Woodrow offered me a job. Nothing to do with tunnelling, mind you. The underground was not really mentioned on my university course.

“So I started with Taylor Woodrow and that was great. I was attached to Wylfa nuclear power station, on Anglesey in North Wales, which was being constructed at the time, but the first job I did was building a hardcore road to take the big oil-cooled cables down from Trawsfynydd nuclear power station to Porthmadog under the Glaslyn estuary and then up to a substation at Pentir near Bangor. That was a wonderful introduction and taught me so much straight away.

“There, I learned how things work. In particular, I learned that nothing quite happens to plan, and that you have to be aware of that and have the contingencies in hand to be sure of things happening.

“At Wylfa I remember almost indelibly the safety part of it. I was involved in prestressing the nuclear vessel there. Pre-stress was provided by big 36-strand tendons using a specially-designed anchor block. Strands were retained by collets, which were essentially circular wedges.

“We were putting a lot of pre-stress on them, and it happened on occasion that you’d hear a little ‘Ping!’ which meant that something had snapped. It might have been just one wire in a strand, but this was nuclear so the whole strand had to come out, and to do that you had to de-stress it. You had to do that with great care because you first had to take it over stress to release the collets and the danger was the whole strand would snap in which case the collets would become very fast and very big bullets. If that sounds unduly dangerous today, back then we just thought of it as normal and took appropriate precautions. It was how things were done.”

He got his first bit of underground work sinking a shaft at Hartlepool, again at a nuclear power station, to link up with the outfall tunnel, and then more doing Central station at Heathrow airport.

“From Heathrow I went up to the tunnels in Gateshead, on the Tyne and Wear Metro. The contracts manager was Maurice Gooderham, and the Agent was Dai Haycock. When I got there Dai said ‘Don’t think you’re going to do that bit and I’m going to do this bit. We are one team so if I’m not here you’re in charge.’ I said, ‘Oh. I see. But I don’t know much about tunnelling.’ He said, ‘Well, we’d better teach you.’ So we used to sit down at lunchtime and as we ate our sandwiches, Dai would be explaining tunnelling to me on his whiteboard, and instructing me in the golden rules. ‘This is how you’d approach this problem, and this is how this works, and this is what this term means…’ So that’s how I learned about tunnelling – from Dai and his whiteboard over sandwiches.

“That job was characterised by the ground. The south side of the river was all coal measures, so underground we had to work in flameproof conditions. The coal seams outcrop on the side of the Tyne there, and a lot of them had been worked because in the past, although it was illegal; people just dug out coal for their winter fuel. So it was quite difficult ground, quite broken, and punctuated by weak seams. We put a quite staggering amount of grout to try to deal with it, something like 130,000 tonnes of it.

“And you didn’t put too much pressure on because you never knew where the grout was going to come out. It would start springing up through the seams all over the place. I remember there was one garden where you just saw the tops of the Brussels sprouts poking up over our grout. But these things happen (we of course made sure that everything was properly restored) and that was my real introduction to tunnelling. It got me understanding the fundamentals, although I never really started at the bottom. To this day, I think that’s a bit of a shame and I rather regret it.”

Engineering and delivering projects, he says, is mainly a matter of people. And that was demonstrated on the Isle of Sheppey.

“It was a coastal protection job, and it had got into trouble. A kilometre and a half of clay beach cliff was deteriorating, and the beach was being washed away. The company decided to change the whole senior team and I went there as project manager. “There were a number of real issues. One of them was the Resident Engineer. He was a man who was seen as a problem but actually we became real good buddies. The problem was that he was very experienced, he knew what he wanted, and he wasn’t getting it and that was really bothering him. I brought in some new workers, from up in Gateshead and Glasgow and I remember the day my chief carpenter walked onto the site with an adze, to shape the planks for the groynes. I can remember the smile coming over the RE’s face. ‘Aaah! Just what I’ve been waiting for!’ Half of engineering is getting the right people in the right place at the right time. The other half is setting up the right attitude and actually understanding really what the problem is. And that is as true now with TBMs as it was in the days when they did it with a pickaxe.

“The carpenters on site were demoralised as well. Their productivity was dreadful. In those days, engineers were responsible for setting and measuring outputs against production targets for paying the workforce, so I said ‘Right, I tell you what we’ll do. I will draw you up a graph: one axis is output in terms of the area of formwork fixed against all worked hours; the other axis is money. And that will set the bonus rate per hour.’ We were talking about handling really difficult shuttering, and it was tide-dependant work so if you didn’t start casting by a certain time, you were in trouble. The productivity improved dramatically, and the tide work proceeded on target. I took terrible stick from my director for offering them so much money. But, I said. ‘Just look at the productivity’. My director kind of went silent, then said in a resigned sort of voice ‘Ah. I see what you mean. But it won’t go on for long, will it?’ They worked so fast that it didn’t go on for long: we got the job done and it was money well spent. That was quite an experience.”

There was a brief interlude when he moved to the oil side of the business for Taywood Santa Fe as a quality engineer. There, he learned about not only oil pipelines but also databases. “Any experience is good experience,” he says about that. But when the price per barrel plummeted, he returned to the UK and to tunnelling in earnest.

“We did the Piccadilly Line Extension to Heathrow Terminal 4. That’s when we really got into making precast linings. We developed a slick system that would lift the whole ring of segments in four bundles down onto a car at the shaft bottom. We took these segments down to a shielded Dosco machine that had a had a very simple gullwing erector. It wasn’t a new system, but we made some tweaks to it and we broke records.”

He was really getting into tunnelling by this time and was about to get into it in the biggest way possible. “Towards the end of that project, at the tail-end of 1984, I was just settling down for Christmas and I got a phone call: it was Ross McKenzie, who was Director in Charge of Tunnelling at Taylor Woodrow – ‘Can you be here on Saturday?’ he said. ‘We think the Channel Tunnel is on, our Chairman Frank Gibb is very supportive and I want you to get involved in it.’ So, the following week I was privileged to be sitting down, around a table with others and the famous ‘Gang of Four’ who were driving the revival of the project and we got started on it.

“The five companies that comprised the Channel Tunnel Group (CTG) and their advisors had judged it to be financeable, and the minute it was financeable then it meant that it was on. They had convinced Margaret Thatcher that it could be done. She wanted it to be a road tunnel; but as engineers in fact we knew from the outset that the only one that would really be viable was rail, particularly because of ventilation. We were anticipating that vehicle emissions would improve, but in 1984 they were not there yet.”

The project went out for competition with CTG as, by then, a UK-French company. “There were two other groups: one was proposing an island in the middle, one a bridge. I was in the CTG team responsible for putting together the tunnelling side of the submission, being supported by the TW tunnelling division. There wasn’t really much of a design at that stage; Mott, Hay and Anderson (MHA) were on board and they were defining the basic shape but that wasn’t the question. It was instead convincing the financing people that it could be built: that we could deal with things like how we would do it, how would we be sure to meet in the middle, what was the split between Brits and the French, what our basic logistics plan was, how long were going to take to build, how efficient would it be? It was very much: ‘Is construction feasible?’

“So we looked at things like, ‘We’re going to need piston ducts to take out the air resistance to the trains travelling at high speeds, we’re going to need cooling, we are going to need drainage and power systems; we are going to have cross passages. How many cross passages? How many piston ducts?’

“Our submission was successful, although our Chairman Sir Nicholas Henderson, who had been British Ambassador to Paris, did, at the last minute, have to write into our proposals a clause that in so many years’ time people would look at it again to see if a road tunnel could be built as well. I think that today you could indeed build one. You could probably build it faster and you could probably build it as an add-on. But given that the current one isn’t really making any money, why would you?

“So, anyway, I was there right at the start trying to get the thing away.” CTG had won the concession and set up a client organisation, which was to develop into Eurotunnel Group. For construction, TransManche Link (TML) was created as an Anglo-French consortium of contractors, formed of UK’s Translink Contractors and France’s Transmanche Construction.

“The first thing that developed was that we were building different tunnels. The French were to an extent coloured by their view of the ground. On their side it is very broken compared with the UK side. We’ve got chalk marl, nice and clayey; they’ve got broken white chalk. It did take two or three weeks, at what turned out to be quite a crucial time, and quite a bit of work to get to the point of actually agreeing.

“It became quite comical, really. I remember sitting down with one of their chief engineers to agree what diameter the tunnel was going to be.” He recalls the arguments about having extra cooling in the tunnel. “We believed we would need it,” he says, while the French engineers produced “extensive calculations” to say there would be sufficient groundwater inflows into the finished tunnel to take away all the heat generated by trains moving masses of air. “To be fair, the French side of the tunnel was a lot wetter, which may have influenced their thinking,” he says.

“I remember going to this meeting where they produced lots and lots of figures to prove their case.” But, as a very clever man from MHA said, an enormous amount of energy will be expended to drive a train undersea for 40km, to end up at the same level – or amount of potential energy – as before. Where has the heat gone? “So we agreed we might need cooling,” he adds.

“And that opens one’s eyes to what is actually an important lesson: to always think, firstly, about the fundamentals of an argument. Because it is possible in engineering to produce a marvellous calculation that show what you want it to show but that basic physics will tell you is wrong.

“As the project went forward it obviously expanded. I had a number of roles over my six years on the project. One of my jobs was to try to coordinate the French and the UK ends, in as much as they needed coordinating, but also to make sure that the design information was flowing from the design office to the right part of the construction at the right time. We had about 5,000 people by then, so it really was a major job.

“Another of my jobs was fire and emergency response. We were building the service tunnel, which was going to be a 22km-long blind heading, and we needed to convince HSE that it could be done safely. It was a big ask. Douglas Parks produced a quantitative risk assessment and we introduced many more safety measures onto the TBM. We didn’t have water curtains, but we did have fire suppression systems, and it was a big problem trying to maintain them in a sea salt environment.

“And the other thing we did, and which the HSE congratulated on, was that we drafted an emergency response manual. The idea was that if we had an emergency, we had to have a set-up that would enable us, from one point at Shakespeare Cliff, to know what was happening underground and maybe 22km away, so that we could tell the Fire Brigade what was happening. We brought all the monitoring together into one central point, we called it the communications centre rather than a control centre because it didn’t actually control anything.

“And there were real issues here because the Kent Fire Brigade had a statutory responsibility to respond to any emergency, but they were not equipped for underground fires. So they were almost obliged to say to us – No, you cannot do that work down that tunnel. In the end we got round it, by establishing a trained experienced dedicated emergency-response rescue squad of ex-miners. Rescue vehicles were equipped with breathing apparatus – which was a first. The arrangement with the Fire Brigade was that that they would attend in any emergency, and advise; they would enter the tunnels only in restricted circumstances because although they were equipped with Long Duration Breathing Apparatus they were not trained to go into the tunnels for any distance or use any of the tunnel transport.

“So the Channel Tunnel was six years of my life. I came away in 1990. Then the Jubilee Line Extension came up.”

His current company is called LBA, and is based next to Borough High Street. London Bridge Associates (LBA) is so named because the founders came from the team that built London Bridge station on the Jubilee Line Extension. Borough High Street (BHS) itself is a major thoroughfare, with shops and residential, leading to London Bridge on the south bank of the River Thames. The new BHS ticket hall was to be positioned under the street.

“The intention originally was to close half the street, build half the ticket hall, and then reopen the half-street and build the other half. But it really wasn’t going to work. So the team developed an alternative proposal: we sank piles either side of the street, put in a full road deck over them, and then excavated, supported the services underneath and constructed the ticket hall. It’s a bit more common these days but then it was very new. We managed to get complete closures of BHS for three weekends to install the road deck; and the whole thing worked brilliantly and we finished well ahead of the three weekend timespan.”

Obviously there would be noise and dust and mud during that process. “So we suggested to any resident who didn’t want to stay while the work was going on that we would fly them to Lanzarote for the weekend. Not many people took it. Some did, and that was fine. It was all the matter, once again, of going about things properly and understanding relative costs. The Lanzarote flights cost peanuts compared to the cost of the project, and it kept people happy and reduced complaints.

“The Jubilee Line Extension was a project with a wonderful team and really good clients. But it got held up early on by the Heathrow tunnel collapse.” In October 1994, tunnels for the Heathrow Express experienced three collapses within three days. Management errors, poor workmanship and quality control were blamed. HSE called it the worst UK civil engineering disaster in the last quarter century.

“The Heathrow project was using NATM, and that is what we were also using. The first thing that happened was we got a request: Would we pause work? Please, could we shut the faces down just temporarily and set up an inspection regime to make sure that they were all safe?

“This was a Friday night, and we were expecting to start again on the Monday. It turned out it was nine months before they let us start again. In Parliament, some minister – I’m not even sure who it was – stood up and said there wouldn’t be any more tunnelling until the problem has been sorted out. And we were in the middle of a very major project. What do you do?

“So in those nine months we tried to get on with everything we could get on with that wasn’t actually NATM (or, as the system in UK came to be developed – sprayed concrete lining (SCL)). We did all kinds of things like changing the design, modifying the ventilation tunnels, changing to precast lined tunnels for instance.

“When we did restart some of the work was fantastic; we squeezed shafts into some really small spaces between buildings. The main station, which you see today as lined with Spheroidal Graphite Iron (SGI) rings, had been intended to be of SCL temporary lining with in-situ concrete secondary lining. However, we realised that the SGI linings we had bought as a contingency could be useful, moving the segments through the work area to catch up the programme.

“We had all kinds of settlement issues and the delay caused some issues because it left temporary works standing for longer than intended, but compensation grouting worked successfully and the BHS deck worked extremely well. The relationships built up at all levels between the project team and the contractors team laid the foundations for a successful, collaboration-driven, turnaround and a successful conclusion. Central to this was that problems were discussed and often solved after work on a Friday when the team would assemble for a beer before the weekend in the Market Porter pub.”

Towards the end of the project Taylor Woodrow decided it was getting out of infrastructure work to become, simply, a housebuilder. “I and others argued against it, but the board thought it would be a less risky business.

“So a bunch of us who didn’t want to be housebuilders – it had been a brilliant team – negotiated a joint payoff deal and set up a series of discussions about our future. We held them above what is now the Brindisi Tapas Bar, which we used as a site office for the contract. As a result of these discussions, we formed a company and called it LBA – London Bridge Associates. The company is still there 23 years on, no longer above the tapas bar but certainly in offices only a few metres away in a beautiful building, in Southwark Street, called the Hop Exchange.

“We left Taylor Woodrow on a Friday and we started as LBA on the Monday putting together the Costain Skanska Bachy bid for the tunnels on the Channel Tunnel Rail Link (CTRL).”

The high-speed rail link was constructed several years after the Channel Tunnel was completed, and was a quite separate project. “There was a small LBA team leading the Joint Venture. The ground was difficult at times, the contract was a tough one, but as a result of forming an agreement with the client, the project manager, and other contractors, the London Tunnels Alliance delivered the tunnels and the Stratford Box on time and on budget – quite rare for a major tunnelling scheme. That is where we really started seeing what collaboration can do.”

Since then, LBA has flourished, in part because of collaboration: it is entirely employee-owned. Project management and consultancy in tunnelling and underground space is its business – “HS1, HS2, Crossrail, Hinkley Point C Marine Works, York Potash, and MetroLink in Dublin have been among our projects, and these days we are looking at consultancy farther afield for example New York using our London Bridge Consultant Network. The challenges, I’m pleased to say, persist but that is what we thrive on.”

And he sums up what he sees as the essentials of engineering: “Look for the pitfalls. Spend your time looking for them and understanding how you’re going to deal with them. Select the right people for your team, understand their strengths, and play to them.

“I would like to add that I have found my last fifty years in civil engineering and tunnelling fulfilling, challenging at times but always enjoyable. There is nothing like the satisfaction of a contract or commission completed on time, to budget, and with a happy client. Hard work is expected and rewarded. I will never be rich but I will be comfortable and I would recommend the life to all young men and women.”