If you glanced at today's Sun you could be forgiven for thinking that UKIP had become not just Eastleigh but Britain's second party. "PM feels heat as UKIP support hits 38 per cent" reads the paper's attention-grabbing headline. But the stat turns out refer to the party's potential level of support, not its current level (12 per cent in today's YouGov poll). Asked whether they would consider voting for UKIP if it had "a realistic chance of actually winning in your local area", 38 per cent say they would, 10 per cent say they would "probably not" and 43 per cent say they would "definitely not". A separate question which asks whether people would consider voting for the party, regardless of its chances of success, found that 36 per cent would and 44 would not.

The level of "considerers" is viewed by all parties as an important measure of their potential to expand their support, so how do the rest compare? It's Labour that comes out on top, with 46 per cent saying they would consider voting for the party and 35 per cent saying they would not. The party's large pool of potential voters is one reason why some Labour MPs (see Peter Hain's Staggers piece yesterday) are confident their party will be the largest after 2015.

The Conservatives are in second place, with 40 per cent saying they would consider voting for the party. But worryingly for David Cameron, 43 per cent of all respondents say they would "definitely not" vote for the party. For a large section of the electorate, the Tories remain too toxic to touch.

But it's the Lib Dems who are now Britain's least favourite party. Only 30 per cent would consider voting for them and 49 per cent would "definitely not". The finding contrasts with an earlier YouGov poll in September 2011 which found that 36 per cent would not consider voting Lib Dem, compared to 42 per cent who would not consider voting Tory. While the Lib Dems are often accused of retoxifying the Conservative brand, the poll reminds us that coalition government has been most toxic for them.

Here are those figures in full.

Labour

Actual support: 40%

Potential support: 46%

35% would "definitely not" vote for the party

Conservatives

Actual support: 31%

Potential support: 40%

43% would "definitely not" vote for the party

Liberal Democrats

Actual support: 12%

Potential support: 30%

49% would "definitely not" vote for the party

UKIP

Actual support: 12%

Potential support: 36%

44% would "definitely not" vote for the party