A LEAKED report has branded workloads at Swanwick's National Air Traffic Services centre "the stuff nightmares are made of".

Excessively long shifts, technological problems and a lack of trust between managers and staff have been cited in the report from a safety review committee.

By law, controllers have to report if the safety of an aircraft under their control is jeopardised by an "overload' of work at the £623m centre.

There were a record 64 overloads last year compared with 28 in 2001 at the old centre at West Drayton in West London.

One controller told the safety committee he was "shaking all the way home" after an overload. Another said overloads were "the stuff nightmares are made of".

A spokesman for the centre said: "Putting this in context, the rise in overload reports covered the first few months of Swanwick operations, when we would expect a higher result as controllers become familiar with the operation.

"Now that the operation has matured, the number has dropped back. There were 18 reports in the first six months of 2003, compared to 39 in the period referred to."

A spokesman for Prospect, the union representing white collar workers, said: "We would not agree with the comments. Our members do not consider there are dangerously long hours, nor would they work in these conditions. They are not insane.

"We work closely with NATS and we believe there is a strong and effective safety culture and there always has been. The centre is proving to be a success. Traffic is increasing steadily and it's coping well."

Swanwick opened five years late in January 2002 after computer software problems, which have continued to plague the centre.

The leaked report said at its most extreme an overload could lead to a controller "losing the plot", but that managers did not consider overloads compromise safety.

It stated: "There was a definite gulf in perception between controllers and managers about the extent to which overloads are taken seriously. This requires attention.''

To the frustration of controllers "too many overload investigation reports concluded with the phrase Actions: Nil.

"This led controllers to believe that the concerns and difficulties that had provoked them to file an overload report were not being addressed."

Between managers and staff there was "us and them" mentality, and "lack of trust, confidence and respect" which the report said "must be tackled".

The report acknowledged that the centre had improved the clarity of the computer screens in November, but it said there were still problems. Controllers were concerned about screens that were out of focus and there was a "garbling" of blocks of text.

One controller told the committee that there was a problem with conversations between pilots and controllers which went unheard by both parties.