The move will result in 1400 job losses between the two facilities, with 550 coming from Southampton and the rest from Dagenham (750) plus logistics and support roles. Ford said it hoped to achieve the staff reductions through voluntary redundancies and redeployment of employees to other locations. The latest job cuts are in addition to an initiative announced earlier this year to reduce the European workforce by 500 positions.

Britain’s biggest union, Unite, which claims to represent the “vast majority”  of  Ford’s “heavily unionised workforce”, accused the company of betraying its workers and warned of the knock-on affect from the plant closures.

Unite’s general secretary Len McCluskey said: “Only a few months ago Ford was promising staff a new Transit model for Southampton in 2014. The planned closures will really hurt the local economies and the supply chain will be badly hit – up to 10,000 jobs could be at risk.”

A spokesman for Unite claimed Ford aimed to redeploy 300 staff but added: “We are not sure this is achievable.”

He criticised Ford’s handling of the closures, saying: “We would have valued the opportunity to talk to the company.”

Unite has vowed to fight the closures through holding mass meetings with workers and collaborating with unions in Europe.

“We want to see the manufacture of Transit retained in the UK,” the spokesman said. “The UK is the Transit’s biggest market so building it nearer to the market would make sense. We remain to be convinced that what Ford is proposing is the right way forward.”

The UK closures, which will take place in July 2013, form part of an overhaul of the manufacturer’s European operations as it scales back in the face of falling demand.

Ford confirmed the Southampton facility produced 28,172 short- and medium-wheelbase Transit vans in 2011 and is forecast to produce 28,239 this year.

A spokeswoman said production has been at this level for three years having stepped up from around 21,000 in 2009. Previously however, the plant had produced about 70,000 units annually.

Ford’s plant in Kocaeli, Turkey assembled 184,500 Transits in 2011 – 78% of the overall total compared to Southampton’s 22%.

When the UK facility shuts down next year, all Transits will be built in Turkey.

Ford has also announced that it plans to close its passenger car plant in Genk, Belgium by the end of 2014.

The company said the restructuring plan would help to address manufacturing overcapacity that had resulted from a 20% drop in total industry vehicle demand in western Europe since 2007. It predicted its European operation as a whole would make a loss of $1.5bn in 2012.

Ford of Europe boss Stephen Odell said: “The proposed restructuring of our European manufacturing operations is a fundamental part of our plan to strengthen Ford’s business in Europe and to return to profitable growth,”

Ford has announced it will build the new Panther diesel engine in Dagenham but has not said how many jobs will result from this development.