The clear inference being that aircraft -- with problems such as bald tyres, defective hydraulics, engine problems -- are being flown back to the UK in the full knowledge that they should be "no go". Furthermore, my source claims, problems with aircraft are known about, and discussed verbally, but are not written into the aircraft log if it is known the problems can be fixed quickly.
I doubt any UK airline pilot would want to get airborne with any of
those defects Ian. However, in respect of lesser technical problems this is exactly what happens in some airlines. The point is that the Captain has to make his decision taking into account
all the circumstances of the flight. Thus a minor defect that is no problem in
one set of circumstances may be a real problem in
another set of circumstances. Sad but true some airlines operations departments will try and argue the toss and pressure the Captain to fly.
Some years ago I was working as a B737 Captain for an airline that is a well known household name. They Board decided to tighten up on delays. The working practice used was to 'have a quiet word' with a number of Captains on the Fleet (typically new commands) about technical delays. It was suggested or implied that it would 'help the company out' if defects were generally recorded on the last landing and not downroute as this might be less disruptive to the schedule.
In my experience a number of junior Captains picked up on this 'hint' and I noticed an increasing tendency for verbal handovers of defects that were strictly MEL items. On one occasion on a midday rotation leaving base I was verbally told of a flap defect that was clearly a no go. I insisted the departing Skipper 'put it in the book'. The flight was probably delayed all of thirty minutes whilst it was fixed.
This topic is one of those hoary old chestnuts that comes round from time to time. It's difficult to get it into the public domain and difficult to stamp out. So yes, it does happen, it's not good and the CAA need always to keep a close eye on tech log entries to make sure the defects are recorded across the network and not predominately at home operating base.
I'm also not sure that company engineers are always, by default, the best option as they too can get caught up in this culture. On occasion I have found a more objective and independent opinion from contract engineers down route. These guys, being outside company culture, can be more quick to ground an aircraft quite simply because there can be little or no comeback on them.