A businessman has said he is considering moving his headquarters to the continent if the UK votes to leave the EU on 23 June.
Dilshad Hothi, who co-founded and runs a business in Bracknell, said Brexit would be "catastrophic".
Conservative MP Penny Mordaunt said: "Moving is not going to give you anything additional."
The MP for Portsmouth North and Labour MEP Clare Moody spoke on a special EU referendum debate for BBC South.
'Not towing UK to Arctic Circle'
Ms Moody replied to audience member Mr Hothi, who employs 300 people, and said: "The point you make has demonstrated that this is not an either or, we trade with Europe or the rest of the world.
"We are perfectly capable from doing both from within the European Union."
In a discussion about trade with the EU and the rest of the world Ms Mordaunt said: "We are not advocating towing the UK to the Arctic Circle."
The politicians took questions from audience members in the debate chaired by political editor Peter Henley.
'Be like Great Britain'
Joe Briscoe, from the Isle of Wight, said due to strict rules he had to work for three years to save enough money so his Chinese wife could move here.
He said: "Is this the sort of thing people who want to marry Europeans would have to face?"
Ms Mordaunt said: "Controlling your borders is not the same as shutting them.
"It is unfair we have different rules which apply to people outside of the EU and those inside."
Ms Moody said reducing immigration would reduce the size of our economy.
She asked the Conservative politician: "Which country do you propose we would be like?"
Mr Mordaunt replied: "We will be like Great Britain."
The BBC South Today EU Referendum Special is being shown on BBC One in the South at 22:35 BST.