The right-wing, Eurosceptic and anti-immigration party UKIP has topped European Parliament polling in Britain – raising questions about the future of the nation’s migration policy and ultimately its membership of the European Union.

UKIP leader Nigel Farage claims to have caused an “earthquake” by securing the “most extraordinary result in British politics for 100 years”. UKIP has won 27.5 per cent of the vote and had 24 MEPs elected.

Labour, on 25.4 per cent, narrowly beat the Tories into third place while the Lib Dems came fifth behind the Green Party. Labour won Wales, the North-West of England, the North-East of England and London where it increased its share of the vote by 15 per cent to 36.7 per cent.

In France, the National Front, led by Marine Le Pen and which also opposes immigration, also polled strongly.

Mr Farage said: “The people’s army of UKIP have spoken tonight and have delivered just about the most extraordinary result in British politics for 100 years.”  He said the three main parties in Britain had led the country into the Common Market but had “twisted and turned” over an in/out referendum on EU membership.

Conservative Prime Minister David has promised to hold a referendum on EU membership before 2017.

He will face pressure to harden up his promise to renegotiate Britain’s relationship with the EU and to reduce immigration to win back the many Conservative voters lost to UKIP.

The results come as official figures show a rise in the arrival of European Union citizens to the UK in the year to December 2013 with net migration remaining unchanged.

The latest figures from the UK’s Office for National Statistics said net migration remained at 212,000, unchanged from the previous quarterly figures.

Separate data shows a 7 per cent rise in registrations of overseas workers to 603,000 in the year to March 2014.

The level of net migration stands at more than twice the government’s target of 100,000 a year.

The detailed figures show that in the year to December 2013, some 201,000 EU citizens came into the UK as long-term immigrants; something officials said was a statistically significant increase of 43,000 over the previous year. Of those, 125,000 came for work reasons, up from 95,000 the year before. However, due to changes in movements of other categories of people, the overall net migration figure remains unchanged.

The ONS said recent patterns of net migration had shown rises over the past two years, but the trend continued to be lower than the general levels seen since 2004.

The ONS said the number of National Insurance numbers issued to overseas workers rose 7 per cent to 603,000 in the year ending March 2014. Of those, there were significant rises in registrations by workers from four EU countries:

• Polish registrations were up by 11,000 to 102,000
• Italian registrations rose by 9,000 to 42,000
• Bulgarian registrations climbed by 7,000 to 18,000
• And Romanian registrations increased by 29,000 to 47,000.

The overall level of immigration remains at approximately half a million people a year while the number emigrating for the long term stood at just over 300,000.

Work remained the most important reason for people wanting to come to the UK, said the ONS, with study second. Another report from the ONS says the net flow of migrants into the UK over a decade has been underestimated by 346,000.

New year-on-year figures show the highest discrepancies came in the first four years after Eastern European countries joined the EU. The ONS realised after the 2011 census that its previous projections had overlooked many people entering the UK.

A review found the main reason was “inadequate sampling” of migrants. “We have known for some time that net migration must have been much higher during the 2001 to 2011 period than the official estimates had suggested,” said an ONS spokesman.

(UKIP, the UK Independence Party was founded in 1993. It describes itself in its constitution as a “democratic, libertarian party” and is reported to have a membership of more than 38,000.)