"Corbyn had the best campaign last year in leadership election"

"I'm not going to get involved in the leadership contest"

London's mayor has warned that a divided Labour opposition leads to the party losing elections, as British politics continues to be hit by fallout from the country's vote to leave the European Union.

In an interview with Al Jazeera, Labour politician Sadiq Khan weighed in on a leadership crisis facing Jeremy Corbyn, but refused to comment directly on whether the Labour leader should step aside.

"When Labour splits, when we're divided, we lose elections," he said.

Khan, London's first Muslim mayor, is a former human rights lawyer and previously held the post of Labour MP for Tooting, a southern district in the capital.

Corbyn has faced a fierce challenge since the Brexit - or British exit - result a week ago. He sacked one shadow cabinet minister for attempting a coup, and more than a dozen other cabinet members resigned, citing ineffective leadership. Many more Labour MPs are also calling for him to step down.

"I've said it loudly and clearly and I’ll say it again: I'm not going to get involved in the leadership contest," he said.

But he did offer some advice for Labour, should a general election be held in the near future - a possibility after Prime Minister David Cameron announced his resignation hours after the result, having failed to convince voters to remain in the EU.

"All I can talk about is my experience during the referendum campaign, and I was concerned that in Manchester and in Leeds and Oldham, and Bradford, Labour supporters weren't aware of what our position was," Khan said.

"To win a big election, a general election, whether it's Mayor of London or whether it’s to be the government … you don't just speak to Labour supporters from the last election, you need to speak to Conservative supporters from the last election, Liberal Democrat supporters, Green supporters, and UKIP supporters … and those that stayed at home, to persuade them to vote for your party."

In 2015, Corbyn won the Labour leadership contest in a landslide victory.

Khan was among 36 MPs who nominated the 67-year-old.

"I don't regret that at all," he said. "I think it was right for the Labour movement to have a choice and to be fair to Jeremy Corbyn, last year, he had the best campaign ... last year, fairly and squarely he won the contest."

Post-Brexit London

A series of racist incidents were reported following the UK's decision to leave the European Union. The Leave campaign had focused its attention on how immigration was harming the economy.

"We've got to stamp this out," Khan said. "[In London] we don't simply tolerate difference. We respect it, we embrace it and we celebrate it."

London voted overwhelmingly in favour of remaining in the EU.

He added that the capital should have a say in negotiations when Britain begins the process of divorcing the bloc.

"When this government comes to do a new deal with the EU, we still have access to the single market - that's crucial for jobs, trade and investment.

"London is the only region in England that voted to remain by a decent majority. The country needs London to do well ... if London does well, the whole country prospers."

For the full interview with Sadiq Khan, watch UpFront on July 1 at 19:30GMT or click this link