In a highly partisan New Year message, the Sheffield Hallam MP accuses his Conservative coalition partners of putting the economic recovery at risk by “flirting” with an exit from the EU.
Equating being in Europe with “jobs, trade and prosperity”, he critises the Tories, along with the UK Independence Party and Labour, of putting politics ahead of the national interest.
The Liberal Democrats go into May’s elections defending 12 seats including two in Yorkshire held by Rebecca Taylor and Edward McMillan-Scott.
The party needs a good showing in the European elections, along with local elections held on the same day, as it looks to build momentum ahead of the General Election in 2015.
Mr Clegg said: “Ukip want out. The Conservatives are flirting with exit. And Labour just don’t have the courage of their convictions on this.
“All three would put narrow political interests ahead of the national economic interest.
“So, in a few months, I’m going to ask you to make a different choice. The Liberal Democrats are Britain’s Party of In. Not because we’re in love with the EU, or we think it’s perfect but because being in Europe means jobs, trade and prosperity”.
Mr Clegg – who appointed former Scottish Secretary Michael Moore as his adviser on European business as part of the campaign to promote the pro-EU case – said the UK’s biggest firms calculated membership was worth £3,000 per household per year.
“So in May, be for ‘in’,” he declared. “Don’t wait for a referendum. Don’t wait for the general election. Make your voice heard now.
“Once Britain finds itself with one foot out the door we won’t just be able to turn back. So don’t take that risk. Don’t let anyone jeopardise our recovery. This year let’s keep Britain in Europe, in work; no shocks or surprises, just better times ahead.”
Mr Clegg also sought to play down expectations for the coming year – suggesting that what the UK needed was “a year of stability rather than surprises” to “lock in” economic recovery.
Mocking the “exciting breathless predictions” of party leaders’ New Year messages in the past, he said: “Not this year. Not from me.
“After a long period of drama and upheaval in the economy, how about a year of stability rather than surprises? More steady as she goes, than spectacular highs and lows. Finally there’s light at the end of the tunnel.
“The economy’s growing, businesses are hiring, 30 million people are now in work – that’s a record high. So how about we make 2014 about one thing and one thing only: locking in our recovery.
“The people of Britain have already sacrificed an extraordinary amount.”
For all the efforts the Government was making to help people with the squeeze on household budgets, “ultimately, we’ll only take the pressure off for good by building a stronger economy, paying down Labour’s deficit, investing in the things that drive growth, schools, roads, railways”, he said.
“And by building a fairer society, where everyone can get on in life, through fairer taxes, more jobs, more help for parents balancing work and home. And by sticking to our plan we’ll do both. There is a potential threat to all this.”
Mr Clegg’s use of his New Year message to make a political attack on the Conservatives is a sign of the direction the Coalition is likely to take in the months ahead.
Tensions within the Government have spilled over into the public domain in recent weeks with Conservative Party chairman Grant Shapps describing Liberal Democrat Business Secretary Vince Cable as a “rude old uncle” in a spat over immigration.
Public disagreements are set to become more common in the months ahead as the two parties look to establish clear dividing lines for the forthcoming polls.