Far-right and eurosceptic parties have registered big wins in the European Parliament elections in a continent-wide protest vote against financial austerity and widespread unemployment.

The stunning victory of anti-EU, anti-immigration parties such as the UK Independent Party (Ukip) and the National Front in France means those who want to cut back the EU's powers or abolish them completely will have greater say in the next parliament.

The Ukip registered a stunning victory by picking 27% of the total seats while the Conservatives won 24% and Labour 25% of the seats.

Ukip leader Nigel Farage said the voters "delivered about the most extraordinary result that has been seen in British politics for 100 years".

In France and the UK, the thumping victory of the far-right was termed a "political earthquake".

While Farage said "the inevitability of European integration ends tonight," French far right leader Marine Le Pen said the people have spoken unambiguously against the EU's role.

"They no longer want to be led by those outside our borders, by EU commissioners and technocrats who are unelected. They want to be protected from globalisation and take back the reins of their destiny," Le Pen said at the FN headquarters in Paris.

In the UK, Farage said his party's strong performance will have long-term consequences in domestic politics and that the Ukip will fight the general elections next year with a targeted strategy.

"We may well see one party leader forced out of his position and another to reconsider his policy of opposition to a referendum on Europe, and David Cameron will have to take a much tougher negotiating stance. It is now not beyond the bounds of possibility that we hold the balance of power in another hung parliament."

"We will go on next year to the general election with a targeted strategy and I promise you this – you haven't heard the last of us."

Britain's mainstream political parties took a severe blow from the Ukip, which was established only in 1993 and does not have a single MP or council leader.

Provisional results showed the Conservatives could emerge second with 25% seats and the Labour a notch behind with 24% of seats. The Liberal Democrats, humiliated at the hustings, headed to finish fourth.

The strong performance of the far-right in major EU nations will mean this bloc will have double the number of MEPs than in the last house.

According to first official results, the pro-European centre-left and centre-right parties will still have control of the 751-seat EU legislature.

In France, a founding member of the European Union, the National Front, won 25% of the seats while the centre-right UMP was headed to win 21%. The ruling Socialists of President Francois Hollande ended up a distant third with 14% of the seats.

The centre-right European People's Party was set to win 212 out of the 751 seats, with 28.23% across the bloc.