General Election 2015: The Lib Dems and their struggle to be heard during the campaign

Clegg claims that the Lib Dems will be the 'surprise story' of polling day, insisting his party will defy predictions of an electoral mauling

Liberal Democrat leader Nick Clegg speaks at the launch of his party's manifesto (Getty Images)

It has been a frustrating election campaign for Nick Clegg and the Liberal Democrats, who have had to shout much louder than they did five years ago to be heard above the competing SNP, Green and Ukip voices.

They have also been forced on to the defensive, facing the wrath of left-leaning voters –who have never forgiven them for getting into bed with the Tories – while struggling to gain credit for Coalition achievements. In addition, voters of all stripes remember their notorious U-turn over university tuition fees.

Their strategy was to circle the wagons around their 56 existing seats and optimistically set their sights on a few potential gains, including Maidstone and Watford.

As polling day approached and the opinion polls showed little sign of the traditional Lib Dem campaign “bounce”, they scaled back even those ambitions and quietly focused on fewer constituencies.

Mr Clegg, who rounded off campaigning by travelling from Land’s End to John O’Groats in a day, will feel he has done as much as he could to keep the party’s flag flying under adverse conditions.

He performed relatively strongly in his two television debates. The Cleggmania of 2010 is long gone but to be named as better than David Cameron and Ed Miliband by 19 per cent of viewers after their three-way clash was moderately encouraging when the party was flatlining on nine per cent.

While the Lib Dem leader covered the vast distances between far-flung constituencies, he had a serious problem in his own back yard: Labour launched an audacious attempt to capture Mr Clegg’s Sheffield Hallam constituency, despite the 15,284 majority he enjoyed over his Conservative rival.

Four hundred miles north in Inverness, his closest ally, the Treasury Secretary Danny Alexander, was facing an apparently unstoppable challenge from the SNP that tied up most of his time on the campaign trail.

It's been a long campaign for Liberal Democrat leader Nick Clegg (Getty Images)

The Lib Dems’ pitch was to present themselves as a moderate, centrist force that would restrain a Tory leadership dragged to the right by Ukip and a left-leaning Labour Party in thrall to the nationalists. In their most repeated slogan, they pledged to bring a “heart” to a Cameron government and a “brain” to a Miliband administration.

The struggle to be heard meant the Lib Dems belatedly announced a series of “red lines” in potential Coalition negotiations, a fortnight after they sidestepped questions on their post-election tactics.

The party’s main sticking points include the boosting of “cradle-to-college” education funding, spending £8bn more on the NHS by 2020, bringing in a “stability budget” by late June and giving pay rises to public-sector workers.

Nick Clegg with his wife Miriam Gonzalez Durantez after voting at Hall Park Centre in Sheffield (PA)

The party also won headlines when Mr Alexander told The Independent that a senior Tory had remarked: “You take care of the workers and we’ll take care of the bosses.” It then openly leaked Conservative plans for welfare cuts that it claimed to have blocked.

Neither of the publicity-seeking moves was calculated to improve the atmosphere in any Coalition negotiations but the Lib Dems’ priority has been to survive with as little damage as possible.

Mr Clegg claimed that the Liberal Democrats will be the “surprise story” of polling day, insisting his party will defy predictions of an electoral mauling.