David Lammy has slammed Brexit Party MEP Ann Widdecombe for her debut speech comparing Brexit to slaves rising up “against their owners”.
On Twitter he said it was “impossible to explain” how offensive her words were.
“Anne [sic] Widdecombe just compared Britain leaving the EU to "slaves" rising up "against their owners", he wrote.
“It is impossible to explain how offensive and ahistorical it is for you to equate my ancestors tearing off their chains with your small-minded nationalist project. Shame on you.”
Mr Lammy's message has been re-tweeted 8,500 times and received 6,400 comments.
Some were supportive of the Labour MP, while others accused him of playing “the race card”.
Ms Widdecombe made her maiden address to the European Parliament in the French city of Strasbourg on Thursday.
The former Conservative MP said Britain is glad to be leaving the trading bloc.
“There is a pattern that is present throughout history of oppressed people turning against their oppressors: Slaves against their owners. The peasantry against the feudal barons,” she said.
A Downing Street spokeswoman said the Prime Minister does not agree with Ms Widdecombe’s description of Brexit as “colonies liberating themselves from their empires”.
“I think it is safe to say that isn't a characterisation that she would recognise nor is it a phrase that she would ever use to describe leaving the European Union,” she said.
The newly-elected UK MEPs may sit in the European Parliament until the country formally leaves the EU.