Senior supervising engineers Mike Jenkins and Kevin McManus have been working on the JLE since the start - before the job actually started in the ground. Both have a clear view on how the job developed.
Jenkins has been in charged of Westminster Station, arguably the most complex of all the station on the project. His view is that the JLE got off to a particularly bad start long before work even started.
'Design is the number one priority on a job like this,' Jenkins concludes. 'If you get the design right you will start along a successful route. If you do not then you head down a path to doom.'
He points out that since the project was designed in the early 1990s, changes in legislation and in people's expectations have resulted in many changes in the detail. Even the industry's approach to risk management is substantially different to that of a decade ago. 'All the small things add up,' he says. 'All disruptions on a job like this have often unforseeable consequences.'
But Jenkins admits that as a client JLEP could have performed better. 'I am certain that we did not always deliver - no client ever does, no designer ever does,' he admits. 'But we have been performing very highly and the mishaps are not rooted in the project team or contracting team at Westminster.'
He says that at Westminster a form of partnering was introduced at the end of 1995 and firmly believes that without it the job would not have got to where it is now. But while he says it wiped out a large amount of history, there was always an adversarial contract to administer which underpinned everything that went on.
'It is not inevitable that the job would finish late and over budget, but you must consider the problems that always dog such big projects,' he explains.
But as far as Jenkins is concerned, the Balfour Beatty Amec contracting team has perform extremely well. 'On a normal £100M contract there might be three or four difficult jobs,' he says. 'Here we had them at such regularity that we did not really have the time to properly plan each operation. But BBA certainly have not dropped the ball during the five years on site.'
McManus has seen some action on Contracts 101, Green Park, and 105, at Bermondsey. He prefers to focus on what has been done well on the JLE.
'When you consider what has been achieved, it has been an astounding success,' he insists. 'We have laid down new standards of safety, the regeneration effects of the scheme are astounding and introduced a whole section of the capital's population to the Tube.'
He is keen to stress that while acknowledging the many failures on the project, it should be remembered that no other project in the past had been so ambitious. .
'We keep castigating ourselves but it need not be simply another heroic failure,' he maintains. 'The original programme was very, very difficult and certainly very tight. The suggestion that it was under budgeted to start with is probably, with hindsight a correct one.'