CONSERVATIVES have defended Zac Goldsmith's London mayoral campaign after Sadiq Khan secured a resounding win for Labour in the capital.

The Tooting MP became London's first Muslim mayor after securing 57% support following a bitter campaign which saw senior Tories try to link him to Islamic extremists.

Defence Secretary Michael Fallon, one of those who hit out at Mr Khan, said it was all part of the "rough and tumble" of an election campaign.

Meanwhile, the lengthy counting process following the "Super Thursday" elections continued, with further results expected in Northern Ireland.

After the last declaration on the first day of counting, 81 of the 108 seats at Stormont were filled, with the Democratic Unionists and Sinn Fein on course to retain their position as the major parties in the power-sharing coalition administration.

READ MORE: London mayoral victory lifts election gloom for labour

DUP leader Arlene Foster said she was "confident" of continuing as First Minister after topping the poll in Fermanagh and South Tyrone.

After the success in London, Labour will also hope for a victory in Bristol's mayoral contest, where Marvin Rees is aiming to oust independent George Ferguson.

A handful of English councils were also expected to declare their results later.

Mr Khan's victory in London was hailed by Labour, with former rival and Tottenham MP David Lammy suggesting it could pave the way for an ethnic minority candidate to enter Number 10.

Mr Fallon defended the approach taken by the Conservatives in their effort to hold on to City Hall despite criticism from senior colleagues.

The Defence Secretary branded Mr Khan a "Labour lackey who speaks alongside extremists" during the mayoral race, and was repeatedly challenged on the BBC Radio 4 Today programme to say whether he was worried about the capital's security with Mr Khan in City Hall.

"London is safe with a Conservative Government working with the new Mayor of London," he said.

Tory former justice secretary Ken Clarke told the BBC the way the campaign had been run was a "mistake" and "probably had a counter-productive effect".

But Mr Fallon said: "Both candidates were asked questions about their backgrounds, their personalities, their judgment, the people they associate with. That's the nature of our democracy and the rough and tumble of politics."

The results in London and across England mean Labour leader Jeremy Corbyn has survived his first nationwide electoral test, but critics - including within his shadow cabinet - continued to express doubts about him.

Speaking during a visit to Sheffield on Friday, where Labour held on to a safe Westminster seat in a by-election, a smiling Mr Corbyn said: "All across England last night we were getting predictions that we were going to lose councils. We didn't. We hung on and we grew support in a lot of places."

But shadow Scottish secretary Ian Murray - Labour's only MP in Scotland - reflected deep unhappiness among MPs opposed to their leader's left-wing agenda when he told the BBC: "I don't think that the public see the UK Labour Party led by Jeremy Corbyn at the moment as being a credible party of future government in 2020."

Veteran backbencher David Winnick called on Mr Corbyn to consider his position in order to give the party a chance of regaining power at the general election.

"The party faces a crisis and the onus is on Jeremy himself. He should decide whether his leadership is helping or hindering the party," he told the Press Association. "I think all the evidence shows that it is not helping."