LONDON (AP) — Britain's upstart Euroskeptic party vowed Monday to build on its historic victory in the European Parliament polls, expressing confidence that it is on course to break into Britain's Parliament for the first time during next year's national elections.

The U.K. Independence Party, which has rode to prominence on a wave of anti-immigration sentiment, scored a sweeping win in the European polls, picking up almost 28 percent of votes to beat Cameron's Conservatives and the opposition Labour Party.

It was the first time in over a century that a national vote has not been won by either the Conservatives or Labour, as voters spurned mainstream parties across Europe to embrace Euroskeptics and nationalist politicians.

The Daily Telegraph paper called the results the "biggest shock to the British political system in a generation."

In a victory speech, UKIP leader Nigel Farage disparaged the main parties as "like goldfish that have just been tipped out of the bowl onto the floor."

The win is a milestone for UKIP, which wants to pull Britain out of the 28-nation bloc but currently has no role in Britain's Parliament. Farage said he now plans to get "a good number of UKIP MPs (lawmakers) elected next year."

Cameron's Conservatives came in third place, narrowly beaten by Labour. But the results were most disastrous for the Liberal Democrats, the left-leaning junior partner in the coalition government. The Lib Dems' leader and Britain's deputy prime minister, Nick Clegg, said he would not capitulate to strong pressure for him to resign.

Cameron said he has drawn lessons from UKIP's win and understood that Britons are "deeply disillusioned" with the EU.

He said his Conservatives will stick to their pledge to offer a referendum on Britain's EU membership if elected at the next general elections.

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