Sadiq Khan has called for the government to delay the process of leaving the leaving the European Union until late 2017, allowing Brexit negotiators time to “square the circle” of ending freedom of movement into Britain, while retaining access to the single market.
Waiting to trigger Article 50 – the mechanism to begin withdrawal from the bloc – until after the German and French elections next year, he said, would give new leaders a chance for “latitude” over the terms of the UK’s departure from the union.
Speaking to Sky News for a documentary about Brexit, Mr Khan said: “I lost the argument and now it's for them to persuade the EU how we can get the best of both worlds, how it's possible to have access to the single market and not have free movement of labour.
“Maybe waiting for French and German elections to be out of the way gives the new French president or German chancellor more of a chance for latitude for some of the things that the British public say we need.”
He called for the government to be “very very careful” about when to trigger Article 50, highlighting business concerns over the terms of new trade deals.
He said: “If we serve notice too quick to quit there's no guarantee jobs won't leave.
“I know for a fact there are people from Paris, Berlin, Dublin courting business leaders as we speak."
He also said there was “no evidence of a plan” from Brexit campaigners, and said delaying the process of leaving would give negotiators the time to come up with one.
“At the moment, businesses aren't leaving,” he said. “At the moment they have hope. “They are being reassured by myself and others that we have a plan in relation to getting the best deal possible.
“Once we serve notice, then the stopwatch starts, the countdown begins and it becomes more difficult rather than easier.”
Mr Khan also said the UK has “got to have access to the single market”.
However, European leaders have repeatedly said that Britain cannot bypass any of the key liberties of the EU and hope to retain access to the single market.
In the wake of the referendum, Angela Merkel said the UK will not be in a position to “cherry pick” the terms of its departure from the EU.
Mr Khan’s predecessor, Boris Johnson, said that after the Brexit vote: “There will continue to be free trade and access to the single market.”
But EU diplomats responded telling Mr Johnson: “It is a pipe dream. You cannot have full access to the single market and not accept its rules. If we gave that kind of deal to the UK, then why not Australia or New Zealand? It would be a free-for-all.”
And Germany’s foreign policy spokesman Jurgen Hardt said such a deal was “not a realistic option”.
He said: “The single market is the harmonised market with four liberties – you can move your money as you want, you can send goods where you want, you can do services where you want, and you have the free movement of employees and citizens.
“Taking [these aspects] out of the single market to keep Britain in is not a realistic option.”
Prime Minister Theresa May has suggested she would not trigger article 50 until after January 2017, and has said she would delay doing so until there is an agreed “UK approach” to Brexit that is backed by Scotland, which voted to remain in the EU.