Andrew Grice: With figures like these, Clegg faces a painful 2011

Nick Clegg is said by aides to have returned from his Christmas break in Spain with a spring in his step. He will need it. Today's "poll of polls" is a rather chilling reminder of the mountain he has to start to climb in 2011.

It reinforces the need for the Liberal Democrats to somehow appeal to a new group of voters after suffering a haemorrhage of support to Labour. It also puts a question mark over Mr Clegg's strategy of taking "full ownership" of the Coalition's decisions – even unpopular ones such as spending cuts and university tuition fees of up to £9,000 a year. The Deputy Prime Minister is convinced that his party would reap no dividend at all if it tried to let the Conservatives take the blame for the nasty medicine needed to cure the country's economic ills.

He hopes the Liberal Democrats will eventually get a reward for facing up to hard decisions, by showing they can be trusted in Government and are no longer a wasted vote.

But Professor John Curtice, who compiled the "poll of polls", suggests that history is not on Mr Clegg's side, citing the Liberal Party's poor 1979 election result after the Lib-Lab Pact of 1977-78.

Today Mr Clegg will re-enter the fray by campaigning in the Oldham East and Saddleworth by-election, which takes place a week tomorrow – the first in a series of tests which will make 2011 a very difficult year.

Another messy policy decision looms on whether to keep control orders for terrorist suspects who are not charged.

The March Budget will be another test, followed in May by difficult elections to the Scottish Parliament, Welsh Assembly and English councils. More important will be the referendum on the same day about the voting system, an historic opportunity to replace the first-past-the-post system with the alternative vote.

Mr Clegg may be upbeat after recharging batteries flattened by the draining controversy over tuition fees. But he knows that things may get even worse before they can get better.