BOMBARDIER is seeking up to 400 additional temporary staff for its train-building plant in Derby, but the company is warning that the present demand could be shortlived.

The Litchurch Lane site is the last traditional train-building plant in the British Isles, and has benefited in recent times from a surge in orders, both for National Rail and also for Transport for London, which is renewing several key Underground fleets.

The first air-conditioned subsurface Underground train has just entered service on the Metropolitan Line, and it will be followed by about 190 more from the Derby works. When the order for S-stock is complete, the entire Underground subsurface fleet will have been replaced, allowing A-stock, C-stock and D-Stock to be retired.

Bombardier has also been building a replacement fleet for the Victoria Line, to replace trains built in the late 1960s, and Class 172s for TfL's only non-electric London Overground line, between Gospel Oak and Barking.

For National Rail, the company is currently supplying Electrostars for National Express East Anglia.

But further ahead, the outlook is uncertain. A decision about a major new fleet for Thameslink has been put on hold, and other potential orders have also been suspended until at least after the government's autumn spending review.

Neil Harvey of Bombardier said: ""We have a spike in our activity, with three to four contracts all reaching their busiest periods.

"But it must be emphasised that these are temporary positions. Once these contracts have ended, we need more work."