Nick Clegg to launch 'aggressive' pro-EU campaign in direct challenge to the rise of UKIP who could top polls in Euro elections Lib Dem leader in high-risk drive to make the case for Brussels UK Independence Party's anti-EU stance has struck a chord with the public Strategists fear Lib Dems could be pushed into fifth place behind Greens Voters to elect 73 MEPs for the UK in May's European Parliament elections Nick Clegg is to launch an â€˜aggressiveâ€™ defence of the European Union in a direct challenge to the rise of the UK Independence Party. The Liberal Democrat leader will use his New Year message next week to pitch his party as the only one â€˜fully committedâ€™ to Britain remaining in the EU. He will argue that with a tide of Eurosceptism engulfing the Tories and Labour wavering about even promising a referendum, only the Lib Dems will make the case as the â€˜party of inâ€™. Aggressive: Nick Clegg will pitch the Lib Dems into the battle over Europe as the only party which unequivocally wants to stay in the EU It is a high risk strategy, with some Lib Dem insiders fearing the party could be pushed into fifth place at next yearâ€™s elections to the European Parliament, behind UKIP, the Conservatives, Labour and even the Greens. In 2009 the Lib Dems polled almost 14 per cent of the vote, but strategists think it could be halved to just 7 per cent in May. However, it is understood Mr Clegg has rejected advice to play down his pro-European views at a time when the Eurosceptic UKIP is in the ascendency. Instead he hopes to appeal to the third of voters who want to remain in the EU as it stands, even without the renegotiation promised by David Cameron after the next election. UKIP leader Nigel Farage predicts his party will top the polls in May despite David Cameron's promise of an in-out referendum by 2017 The Tories have promised to hold an in-out referendum on leaving the EU by 2017, but Mr Clegg has argued it would create unnecessary uncertainty. He plans to contrast his clear stance with that of UKIP leader Nigel Farage, who wants Britain to leave the EU altogether. Mr Clegg will use the European elections to argue that abandoning the EU would damage jobs in the UK, hamper police in fighting crime, setback the fight against climate change and undermine Britainâ€™s standing in the world. A senior Lib Dem source said: 'Between March and May the Liberal Democrats will fight an unashamedly pro-Eurorpean campaign as the party of "in." We will present ourselves as the only party fully committed to being in. We will seek to polarise the debate with UKIP. Mr Farage has boasted that he will trigger a â€˜political earthquakeâ€™ by topping the polls in Mayâ€™s elections to the European Parliament. Popular: During 2013 UKIP has cemented its lead in the polls over the Liberal Democrats, ending the year on 10 per cent, according to IpsosMORI UKIP is expected to capitalise on the lifting of work restrictions on Romanians and Bulgarians from January by arguing that only by leaving the EU can Britain take back control of its borders. The source added: 'We might not agree with UKIP but we are both very clear where we stand. They are the party of out, and we are the party of in. Nobody argues the case for reform more passionately than Nick Clegg. But the Lib Dems have always believed you reform Brussels to work better for Britain by having a seat at the top table and leading those debates.