London: European Commission president Jose Manuel Barroso argued Monday that Britain is better in the European Union and warned that alienating its allies would be a "historic mistake", as pressure mounts from British eurosceptics before elections.
"In the years to come the UK could be facing a choice -- to stay or leave the European Union," the outgoing head of the 28-member bloc`s executive body said in a speech at the Royal Institute of International Affairs in London.
"Could the UK get by without a little help from your friends? My answer is probably not."
Squeezed by growing momentum of the anti-EU UK Independence Party (UKIP), Prime Minister David Cameron has vowed to renegotiate the terms of Britain`s EU membership and hold an in-out referendum if he is re-elected next year.
Barroso urged politicians to make "the positive case" for staying in Europe, expressing concern about "negative and false portrayals in... newspapers from Monday to Saturday."
"It worries me that so few politicians on this side of the Channel are ready to tell the facts as they are," Barroso said.
After press reports that Cameron might seek to impose a cap on EU migrants coming to Britain, Barroso told a BBC interview on Sunday that such a limit would be against European law.
"Any kind of arbitrary cap seems to me to be not in conformity with European laws. Because for us it`s very important the principle of non-discrimination," he said.
"The freedom of movement is a very important principle in the internal market: movement of goods, of capital, of services and of people."The Sunday Times this week reported that Cameron was exploring whether national insurance numbers -- personal identifying codes needed to work in Britain -- issued to EU migrants could be capped.
"It would be an historic mistake if on these issues Britain were to continue to alienate its natural allies in central and eastern Europe, when you were one of the strongest advocates for their accession," Barroso said.
Migration to Britain from other countries in the EU, particularly from newer and poorer member states in eastern Europe, is a sensitive political issue in Britain and UKIP has put border control at the heart of its electoral campaign.
The party won its first elected seat in parliament in a by-election earlier this month with the re-election of lawmaker Douglas Carswell, who had defected from the ruling Conservative Party.
UKIP hopes to win a second seat in a November by-election, following the defection of another Conservative MP to the once-fringe party that has risen to around 17 percent support in polls.
The country holds a general election sometime in the first half of next year, with the Conservative party currently running neck-and-neck in opinion polls.
Cameron has vowed to negotiate hard to "get what Britain needs" on immigration, but has not given details on specific proposals.
International Development Secretary Justine Greening, a cabinet minister in the Conservative-led government, said on Sunday that a need to address migration from within the EU meant the rules would have be examined.
"That means taking a fundamental look at some of the rules that allow unrestricted immigration in a way that we don`t think is sensible," Greening told Sky News.