Union bosses today accused Ford of behaving "disgracefully" over the closure of the plant.
Unite general secretary Len McCluskey accused Ford of betraying its workforce and said the announcement had been handled ''disgracefully''.
He 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.
''The Transit has been the best-selling van in the UK for over a quarter of a century.
"It has a future in the UK if this Government is prepared to fight for real jobs and persuade Ford to keep manufacturing vehicles in the UK.''
Justin Bowden, national officer of the GMB union, said: ''This is devastating news for the workers in Southampton and Dagenham and is very bad news for UK manufacturing.
''Ford's track record in Britain is one of broken promises and factory closures. There will be a feeling of shock and anger, and Ford's commitment on investment will cut little ice.''