By Tim Sculthorpe
Sadiq Khan is poised to be elected as the first Muslim London Mayor this afternoon as live results show he has received about 45 per cent of first round votes.
With the Labour candidate on course to a huge margin of victory, the Tory backlash over Zac Goldsmith's 'outrageous' campaign has already begun.
The final result of the race to succeed Boris Johnson will be announced at City Hall later today.
Mr Khan held a 14 point lead over Mr Goldsmith in the final pre-election poll by YouGov, raising expectations of a big victory to add a bright spot to an otherwise mixed night for Labour.
The party collapsed in Scotland, lost its majority in Wales and faced a handful of council seat losses in England.
Andrew Boff, the Conservative leader on the Greater London assembly, said Mr Goldsmith's strategy to attack Mr Khan for his links to Muslim 'extremists' in the race to replace Boris Johnson in City Hall was a mistake.
And in a remarkable broadside on the Tory mayoral candidate, Mr Boff said his party's tactics could damage relations with the Muslim community.
The negative campaign run by the Tories looks set to have failed as a YouGov survey suggested Mr Khan is likely to be 11 points clear of his Tory rival on the first round of voting before he finishes even further ahead once other candidates are eliminated.
The poll indicates Mr Khan is set to shake off the toxic anti-Semitism row which has engulfed Labour for the past week.
Outgoing mayor Mr Johnson today thanked the capital for his eight years in office as he sent his final messages from the official London Mayor Twitter account.
He tweeted: 'It's time to sign off from City Hall - it's been the most amazing privilege to be your mayor.'
Minutes after the polls closed in the London mayoral election last night, Mr Boff criticised Mr Goldsmith's strategy for focussing on Mr Khan's apparent links with radical Muslims, telling the BBC: 'It was effectively saying that people of conservative religious views are not to be trusted and you should not share a platform with them.
He added Mr Goldsmith had 'done real damage' and had 'blown up bridges' that the Tories had built with London's Muslim communities, adding it was a mistake to 'equate people of conservative religious views with sympathising with terrorism'.
'I mentioned that I thought this was a mistake for future integration in London. If you are a London politician this is just a bizarre thing to do,' he said.
'I do believe it's going to affect Conservatives at the sharp end, especially in those parts of London where there is a high Muslim population.'
The final poll, by YouGov for the Evening Standard, suggested a comfortable win for Mr Khan today - forecasting a 57 per cent to 43 per cent margin for the Labour candidate.
Voters in the London Borough of Barnet reported problems at polling stations yesterday and said they were being turned away and told to come back later.
If the result across London proves to be closer than expected, the difficulties in Barnet could provide the basis for a legal challenge to the whole result.
Richmond MP Mr Goldsmith launched a 24 hour campaign blitz, making visits across the capital to venues including a kebab shop, milk round and a street market to try and avert defeat earlier this week.
And in the Commons earlier this week, Mr Cameron used Prime Minister's Questions to build on the controversial campaign to link Labour to extremism.
He angrily challenged Mr Corbyn over alleged links to Hamas and Hesbollah.
Mr Corbyn initially tried to dodge the issue, insisting: 'I have made it very clear Labour is an anti-racist party and there is no room for anti-Semitism.'
But under intense pressure he then conceded that any group that committed racist or anti-Semitic acts was 'no friend of mine'.
The attack came after Israeli ambassador Mark Regev delivered a thinly veiled attack on politicians who 'embrace' Hamas, the armed wing of which is banned in Britain as a terrorist group.
A good night for Jeremy Corbyn if: Any net gain of council seats would be an extraordinary achievement given the low expectations. Even keeping losses below 100 would appear a result.
A big win for Sadiq Khan in London will add gloss to whatever poor results turn up elsewhere in the country.
Holding on to second place in Scotland and stemming losses in Wales to ensure Carwyn Jones stays as First Minister.
But it's a bad night if: Losing more than 220 council seats would be a worse performance than Michael Foot managed in 1982. It would send the Labour vote share below 30 per cent.
Losing London would be a catastrophe even given low expectations elsewhere.
A good night for Tim Farron if: Any signs of recovery would be welcome for the Liberal Democrats after last year's general election mauling. Gaining more than 50 seats would be a welcome return to the political map.
Defying the polls to get back on the constituency board in Scotland and resisting the Ukip advance in Wales.
But it's a bad night if: Losing anything would show the party still has not reached rock bottom. Questions would be asked about how much further the Liberal Democrats can fall while remaining a going concern.
A good night for David Cameron if: Zac Goldsmith pulls off an improbable win in London and holds on to City Hall for the Tories.
Gains worth 100 seats or more in English councils, keeping hold of key fortresses in middle England.
Seizing second place in Holyrood and installing Ruth Davidson as leader of the opposition north of the border.
But it's all gone wrong if: Losing seats to Jeremy Corbyn anywhere would be a bad sign and could leave Tory administrations vulnerable in places like Trafford and Castle Point.
A big loss in London would make it appear as if the campaign tactics had backfired - despite the PM escalating charges of extremism even further at Prime Minister's Questions.
A good night Nigel Farage if: Winning the party's first ever seats in the Welsh Assembly and London Assembly.
Increasing the party's haul in the English councils would be an encouraging sign of progress, particularly if Ukip seize control of councils overall.
But it's a bad night if: A fourth bad year of local election results would make plain the failure of the party to make progress outside of the EU issue.
The party fails to make progress in Wales and misses out on the chance for its first ever seats in Cardiff Bay.