Khan defends campaigning with Cameron for Remain vote
Sadiq Khan has defended campaigning with David Cameron in the EU referendum, saying he wants to make it clear Labour supports a Remain vote.
It comes after shadow chancellor John McDonnell said sharing a platform with the Conservatives "discredits" Labour.
A spokesman for Mr Khan said many Labour voters did not know the party's EU stance, and he would take any opportunity to spread the message.
Mr McDonnell later insisted he was not criticising Mr Khan personally.
While most Labour MPs support a Remain vote, Jeremy Corbyn is regarded as the most Eurosceptic leader of the party in a generation and the Vote Leave campaign is chaired by a Labour MP, Gisela Stuart.
Mr Corbyn is campaigning for the UK to stay in the EU, but he has been urged by some in the party to make a bolder case for membership.
'Discredits and demotivates'
Mr Khan made a joint appearance with the prime minister on Monday to launch a Britain Stronger In Europe battle bus and pledge card aimed at persuading voters to back Remain.
The show of cross-party unity came after Mr Cameron repeatedly attacked Mr Khan during the London mayoral contest for having a history of sharing platforms with extremists - a claim firmly rejected by Mr Khan.
According to a report by Politics Home, Labour's shadow chancellor, Mr McDonnell - who, along with Mr Corbyn, has refused to campaign with the Tories in the referendum, despite being on the same side as the government, appeared to criticise Mr Khan's decision.
Asked whether Labour should put aside its differences with the Tories to campaign for a Remain vote, Mr McDonnell was quoted as saying the two parties did not share the same vision of Europe, and accused Mr Cameron of wanting to do away with workers' rights.
"Sharing a platform with them discredits us. It demotivates the very people we are trying to mobilise," he is reported to have said at a Labour In for Britain event.
However, speaking to the BBC later, Mr McDonnell denied he was criticising Mr Khan, saying: "I never mentioned Sadiq Khan's name at all."
He said the party had "learnt the lesson" of the Scottish independence referendum, when it campaigned alongside the Conservatives.
And he added: "It doesn't help us appearing on platforms with Tories because they have a differing view of Europe. So this is a distinct Labour campaign, and as a result of that I think we'll be able to mobilise Labour votes."
'More work to do'
A spokesman for Mr Khan said he had made it "crystal clear" he would campaign with the PM for a Remain vote.
He added: "It is deeply concerning that the polls today suggest that Labour voters are unsure where the Labour Party stands on the referendum.
"Sadiq won't miss a single opportunity to make it absolutely clear to those voters where Labour stands on the referendum."
According to a YouGov poll for the Times, almost half of Labour voters do not know that their party is campaigning for Britain to stay in the EU - and thought it was either split on the issue, supporting an EU exit, or they did not know.
Labour MP and Remain campaigner Emma Reynolds told the BBC the party had "a lot more work to do" to show it was behind a vote to stay.
"What's really important is that we get more Labour voices out there - so that our natural voters, who say they don't know which way we are campaigning, know that we are campaigning to Remain," she told BBC News.