By Adam Brimelow BBC health correspondent

The episode in Cannock - in which a team of German doctors, flown in to help cut NHS waiting lists, quit on its first day - has highlighted deep concerns over what has become known as the flying doctors scheme.

Many consultants have been worried about this whole initiative ever since it was introduced back in the summer.

Dr Guy Routh, chairman of the Consultants Federation, told the BBC: "The teams arrive, usually with little consultation with local consultants, who know the sort of surgery that's taken, know the equipment they use, know the staff they work with."

He said that did not encourage an atmosphere of trust.

It is not just British doctors who have reservations. The German company Germedic was involved in preliminary talks for the scheme, but has now pulled out.

Its chief executive Axel Hollander said: "You have to find additional capacity and I cannot see whether this will be possible in the NHS trusts."

'Could work'

But there are places where the programme is up and running, and overseas teams are helping to cut waiting times.

At first sight the outpatients ward on the third floor of the Royal Lancaster Infirmary looks like any other hospital, but if you listen to the staff as they hurry about their work you will notice all the accents are South African.

This is easily the biggest and most ambitious scheme so far in the flying doctors programme.

There are more than 40 staff aiming to carry out at least 800 cataract operations over four weeks.

Dr Richard Friedland, chief operating officer of the South African firm Netcare, said: "This kind of model could work for other trusts as well, and for other waiting lists."

Local support

But there are many trusts across the country who have decided against it - for reasons of capacity or time, or simply because they thought local recruitment was a better answer.

There have also been practical and bureaucratic problems, which have halted schemes in Taunton and Birmingham.

The chief executive of the Lancaster scheme Ian Cumming said it would succeed because they had won local support first.

That appears to be the most important, and challenging lesson.

There are now five overseas teams in place across the country.

The Department of Health says more will be announced next month.

But it is clear that without the agreement and support of local doctors, nurses and patients, there is every possibility of further trouble ahead.