Who pushed for concurrency, when and where? I'm aware it's been done before, in fact one could argue that every programme in the last sixty years or more has had some degree of concurrency, if you blur the boundaries between further development and actually producing operational airframes before they even reach IOC. I think you could level that at ADV Tornado, which was a disgraceful introduction. And that may well be where some RAF folks here get our scepticism from - when you know there are problems, the more people tell you it's OK, the more you seek to know how it will be so.