The first round results handed Sadiq Khan a big nine point lead and after initial results on second preferences it became impossible for Zac Goldsmith to close the gap''
A London Elects spokeswoman said: 'The returning officer is currently updating candidates and agents. There were some small discrepancies with regard to the mayoral figures and we have to take the time to check them.
'We're doing the checking in conjunction with the Electoral Commission.'
Women's Equality Party founder Sandi Toksvig performed an impromptu stand-up routine as the waiting continued in the London mayoral contest.
Meanwhile UKIP leader Nigel Farage claimed another 'big breakthrough' as his party had two candidates, Peter Whittle and David Kurten, elected to the Greater London Assembly.
Jeremy Corbyn was among the first to congratulate Mr Khan tonight even before the official results of the eleciton were declared
Mr Khan scored more than a million votes on the first round alone and appeared likely to rack up the largest individual mandate in British electoral history once second preference votes were included.
Steven Norris, a former MP and mayoral candidate, insisted it was 'no use having a dog whistle when everybody can hear it' as he led criticism of Mr Goldsmith's campaign.
Andrew Boff, the Conservative leader on the Greater London assembly, said the strategy had been a mistake and could damage relations with the Muslim community.
Roger Evans, a deputy to Boris Johnson at City Hall, also weighed in, warning that Mr Goldsmith's campaign would leave a 'negative legacy'.
In a remarkable broadside on the Tory mayoral candidate, Mr Boff said his party's tactics could damage relations with the Muslim community.
Mr Khan and his family were met by a huge group of reporters as he arrived at London's City Hall for the declaration of the crucial mayoral race
Roger Evans, a deputy to Mr Johnson, also weighed in, warning that Mr Goldsmith's campaign would leave a 'negative legacy'.
And former Conservative mayoral hopeful Steven Norris pointedly said there was 'no use having a dog whistle when everybody can hear it'.
Former Tory chairwoman Sayeeda Warsi said: 'Our appalling dog whistle campaign for London Mayor 2016 lost us the election, our reputation & credibility on issues of race and religion.'
Even Mr Goldsmith's sister Jemima said: 'Sad that Zac's campaign did not reflect who I know him to be- an eco friendly, independent- minded politician with integrity.'
She added: 'Congratulations to Sadiq Khan - 1st Muslim Mayor of London- a city for all cultures, backgrounds & religions. A great example to young Muslims.'
Tory candidate Zac Goldsmith, pictured on the campaign trail, faced a firestorm of criticism from the Tories after losing heavily
Steve Hilton, the former senior advisor to Mr Cameron, said Mr Goldsmith had returned the 'nasty party' label to the Tory party.
He told Newsnight: 'The overall impression I got from Zac's campaign was a rather old-fashioned and frankly uninspiring campaign which I was really surprised about.
'Because Zac, who I know pretty well, is actually a really interesting, thoughtful, somewhat anti-establishment character in politics.
'He's got a very interesting set of views of different kinds on different issues, and it seemed to me that none of that was conveyed in his campaign which to be honest I found really weird.'
Baroness Warsi, a former Conservative Party chairwoman, led criticism of Mr Goldsmith for the way he conducted his mayoral campaign
The extent to which the negative campaign run by the Tories failed was laid bare as the results rolled in.
Mr Khan was rewarded by strong swings in the vote in his favour across the capital and results suggested he won across more of the city than previous Mayors.
The poll result also indicates Mr Khan is set to shake off the toxic anti-Semitism row which has engulfed Labour for the past week.
Bethnal Green-born actor Eddie Marsan sent this tweet to a friend in Calgary, Canada, which already has a Muslim mayor, Naheed Nenshi
New York Mayor Bill de Blasio led international congratulations to the new London Mayor, tweeting: 'Sending congratulations to London's new Mayor and fellow affordable housing advocate, @SadiqKhan. Look forward to working together!'
Anne Hidalgo, the mayor of Paris, offered her 'felicitations' on Twitter, saying she was looking forward to strengthening co-operation between the two capitals on key issues like housing, pollution and culture.
Former Labour leader Ed Miliband said: 'Congratulations Sadiq Khan. You will be an outstanding Mayor of London.
'Your positive vision and dignity beat a campaign of fear and division.'
New York Mayor Bill de Blasio led international congratulations for the new Mayor of London
Tory Business Secretary Sajid Javid said: '@Sadiqkhan from one son of a Pakistani bus driver to another, congratulations.'
Bethnal Green-born actor Eddie Marsan tweeted to a friend in Calgary: 'Bet our Muslim mayor is better than your Muslim mayor.'
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.
'That's outrageous.'
Empty ballot boxes were discarded at the London mayoral count today as the results were finalised this evening
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.'
Outgoing mayor Boris Johnson signed off from his official Twitter account today and said it had been the 'most amazing privilege' to fill the role for the past eight years
