EU referendum: Free movement from Turkey 'will not happen'
Labour MP Chuka Umunna says free movement of people from Turkey within the EU "is not going to happen".
In a special debate programme on BBC One Mr Umunna said the issue is the "biggest project fear story there is".
Leave campaigner and employment minister Priti Patel said she wants to establish a "fair" immigration policy.
Immigration, the economy and security were issues covered by the panel that also included entrepreneur Richard Reed and businessman John Mills.
Mr Mills, who wants to leave the EU and is best-known for founding consumer products company JML, voiced concerns over a living wage of £9 an hour which would be "four times the average wage in Romania and Bulgaria".
"That's going to produce a huge attraction for people to come to the UK," he said.
Ms Priti, Conservative MP for Witham, Essex, said she wants an immigration policy to "end discrimination" and give more chances to people outside the EU.
MP for Streatham Mr Umunna said the number of jobs is linked to European Union membership.
"You have got 1.5m British people employed in EU citizens' businesses here in the UK," he said.
"We have a veto on enlargement of the European Union. Turkey is not going to be joining the European Union any time soon."
Mr Reed, who founded smoothie-makers Innocent and is a member of the Stronger-In Campaign, said: "More than two thirds of immigrants to London are from outside of the EU.
"As a result we have a more joyous, vibrant, fast-growing, wealthy city."
EU referendum issues guide: Explore the arguments
A referendum on 23 June will decide whether Britain should leave or remain.
- 'Better In or Out? A BBC London Referendum Special' presented by Jeremy Vine will be shown at 22:35 on BBC One and BBC Radio London.