Unions are considering strikes if Ford goes ahead with its plan to halve production at its last vehicle manufacturing site in the UK.

They say up to 600 jobs could be cut after the automaker said Monday it will reduce production to 35,000 units a year at its Southampton factory in southern England in 2011.

The new figure is less than half of the 75,000 units of the Transit light commercial van the factory built in 2007.

Brian Bennett, Ford UK corporate affairs manager, said there would be job losses as a result of the proposal, although the details had to be discussed with union leaders.

Ford said the Southampton factory will continue to build the Transit light commercial van until 2011. After that date the plant will build only chassis cab versions of the new Transit.

Chassis cab Transits have a front cab with ladder-frame chassis behind as a base for a standard box van, dropside or tipper bodies.

Starting in 2011, all full-body versions of the Transit will be built in Ford's factory in Kocaeli, Turkey, which built 128,000 Transits last year.

Ford said the changes were necessary to enable the company to make Transits profitably in the competitive European commercial vehicle market.

Roger Maddison, a national secretary for the Unite trade union, said: "Ford is saying the only plan they have for the future of Southampton is for the chassis cab to be built there and 600 jobs to be going."

Meetings will be held with workers Wednesday to decide the next move. The unions have not ruled out going on strike.

Maddison said: "We are saying we want nothing short of the $220 million (about 155 million euros) which would bring the new Transit to Southampton in 2011. Two-hundred and twenty million dollar would be nothing compared to a national strike."

Maddison said Ford employs 13,000 workers in the UK.

Without being specific, Ford promised a multimillion pound investment at the Southampton plant, but Maddison said Ford's offer was just $55 million.

The union boss said workers are "angry and concerned about their future."

Ford said the cut in production at Southampton is unrelated to the current downturn in the European market.

The Southampton factory employs 1,276 workers and has been building the Transit since 1966.