CHUKA Umunna has brushed aside suggestions that the Liberal Democrats are on the slide in the election campaign, insisting the party was polling “at least double” what it was two years ago.

The defence of the party’s campaign by its Foreign Affairs spokesman came as Jo Swinson is today set to launch a direct personal attack on Boris Johnson, accusing him of repeatedly telling lies and dragging the office of Prime Minister "through the mud".

At a joint press conference with Tory peer and fellow Remainer Lord Heseltine, Mr Umunna responded to a question about the latest Ipsos Mori tracker poll, which said 50 per cent of voters were now unfavourable towards the party leader, up from 41 per cent a week ago, and 49 per cent were now unfavourable towards the Lib Dems, up from 42 per cent.

While the net rating for Mr Johnson had worsened from -8 to -14 over the past week and that for Jeremy Corbyn had improved slightly from -39 to -35, the rating for Ms Swinson had worsened significantly from -20 to -31.

Similarly, the net ratings for how good a campaign each party was having showed the Tories were on -7 from -8 a week ago, Labour had improved from -23 to -11 while the Lib Dems had gone from -9 to -20.

As suggestions are being made the party’s Revoke policy is going down badly on the door-step, Mr Umunna was asked what the Lib Dems could do to reverse the slide.

He replied: “It is worth reminding people we are polling at least double what we were in the 2017 General Election campaign, which is a huge step forward for the party.”

Insisting the “whole party machine” would be behind the campaign to Remain, he made a plea to people to use their votes tactically.

“If you want to stop Brexit, we have to reduce the number of Conservative MPs in the next Parliament to start. We can beat the Conservatives in swathes of seats across the UK. Don’t waste your vote by voting for parties that can’t. Very simple.”

Meanwhile, in a speech in London today, Ms Swinson will argue Mr Johnson's whole life has been about becoming Prime Minister "not out of some deep-seated desire to make people's lives better but out of some sense of Etonian entitlement".

She will declare: "Boris Johnson only cares about Boris Johnson. And he will do whatever it takes, sacrifice whatever is needed, to get what he wants.”

The Scot will add: “This is a man who decided which side to support in the EU referendum by game-playing whether it would get him the keys to No 10…You cannot trust a word Boris Johnson says.”