Sadiq Khan has dismissed Donald Trump's barrage of tweets about his response to the London attacks and questioned 'isn't he busy?'.

The London Mayor said he had too much on his plate in the aftermath of Saturday night's atrocity to respond in kind.

The US President has launched a series of tweets at Mr Khan, misquoting a reassurance that Londoners should not be alarmed by the presence of armed police to suggest the Mayor is playing down the terror threat.

Theresa May finally stepped into the row with clear criticism of Mr Trump today, insisting he was 'wrong' to be criticising Mr Khan's response.

Mr Khan has called for Mr Trump's state visit, expected in the autumn, to be cancelled - but the Government had rebuffed the claim.

Sadiq Khan (left today on GMB) has mocked Donald Trump's feud with him as he urged ministers to axe his state visit

Theresa May (pictured campaigning in Wales today) had previously endorsed Mr Khan's work in responding to the London Bridge atrocity but had stopped short of criticising the President

Asked about the spat with Mr Trump, Mr Khan told ITV1's today's Good Morning Britain: 'We're not kids in a playground, he's the president of the US. I'm too busy to respond to his tweets, isn't he busy?'

He denied he was stoking up a feud which went back to 2016, when the mayor described the then presidential candidate's calls for a ban on Muslim entry into the US as 'ignorant'.

'It takes two to tango. I'm not tangoing with this guy, I've got better things to do,' said Mr Khan. 'From Saturday until now my focus has been dealing with the aftermath of the horrific attack. Working with the police, security services, the Government; that's why I've not responded to the tweets from Donald Trump.'

Mrs May told The Sun today: 'The relationship with America is our deepest and most important defence and security relationship.

'Having said that, I think Donald Trump is wrong in what he said about Sadiq Khan, in relation to the attack on London Bridge.

'We've been working with Sadiq Khan. When you're working in the aftermath of an attack like that, party politics is put to one side.

'He's been at the COBRAs and we've been working with him to ensure the response was right, and to get London moving again.'

Last night, Mr Khan said Mr Trump's state visit should not go ahead.

'I don't think we should roll out the red carpet to the president of the USA in the circumstances, where his policies go against everything we stand for,' he told Channel 4 News.

'When you have a special relationship it is no different from when you have got a close mate. You stand with them in times of adversity but you call them out when they are wrong. There are many things about which Donald Trump is wrong.'

Foreign Secretary Boris Johnson (pictured on Sky News today) - Mr Khan's predecessor as London Mayor - backed Mr Khan but dismissed the row as 'trivial' compared to the attacks themselves

Mr Trump renewed his strange fury at Mr Khan on Sunday, blasting him on Twitter for assuring Londoners there was 'no reason to be alarmed'.

The President suggested the remark referred directly to the terror attack when in fact it was about the increased presence of armed police.

But Mr Trump brushed aside criticism of his initial message last night, issuing a fresh Twitter attack on Mr Khan branding him 'pathetic'.

His son, Donald Trump Jr, piled in to the row today telling ABC: 'Rather than the mayor of London attacking maybe he should do something about it.

'Maybe he should do something to fix the problem rather than just sit there and pretend there isn't one. I think that's an important message.'

Mr Johnson told Sky News today: 'I don't want to impose myself to a row between the Mayor of London and the President of the United States.

'I have been there myself. Both individuals are very well capable of standing up for themselves.

'Sadiq Khan was saying something very reasonable and sensible about how there was no need for the public to be alarmed by armed police officers on the streets.

'This is a trivial controversy by comparison with the enormity of what happened on Saturday night and the importance of getting the right response.'

He added on the BBC: 'Well, the invitation has been issued and accepted and I see no reason to change that but as far as what Sadiq Khan has said about the reassurances that he has offered the the people of London I think he was entirely right to speak in the way that he did.'

Liberal Democrat leader Tim Farron also said Mr Trump's decision to go on the offensive in the wake of a major terrorist incident should disqualify him from making a state visit to Britain later this year.

The Prime Minister granted the honour to Mr Trump just days after he took office in January. The trip, in which he and his wife Melania will be hosted by the Queen, is due to take place in October.

Labelling the President 'an embarrassment to America', Mr Farron added: 'Theresa May must withdraw the state visit. This is a man insulting our national values at a time of introspection and mourning.'

Mr Khan appeared to criticise Mr Trump yesterday while addressing police funding. He noted that London has other responsibilities due to its status as a capital city, 'from major events … to state visits – some welcome, some less so'.

Their row began in January, when Mr Khan labelled the President's travel ban 'shameful and wrong'.

Their row began in January, when Mr Khan labelled the President's travel ban 'shameful and wrong'

The trip, in which Trump and his wife Melania will be hosted by the Queen, is due to take place in October

Mr Trump re-ignited it on Sunday after Mr Khan issued a statement, saying: 'Londoners will see an increased police presence today and over the course of the next few days. There's no reason to be alarmed.'

Mr Trump interpreted these remarks as suggesting people should not be alarmed by the second terror attack to hit the capital in three months.

He wrote on Twitter: 'At least seven dead and 48 wounded in terror attack and mayor of London says there is 'no reason to be alarmed!'

The President suggested the London attacks vindicated his opposition to gun control, saying: 'Do you notice we are not having a gun debate right now? That's because they used knives and a truck!'

The London mayor's office responded by saying he had 'more important things to do than respond to Donald Trump's ill-informed tweet that deliberately takes out of context his remarks'.

But last night, Mr Trump stepped up the row, posting another message on Twitter, saying: 'Pathetic excuse by London mayor Sadiq Khan, who had to think fast on his 'no reason to be alarmed' statement. MSM [mainstream media] is working hard to sell it!'

Mr Trump interpreted Mr Khan's remarks as suggesting people should not be alarmed by the second terror attack to hit the capital in three months

Mr Trump's attack on the mayor has alarmed some senior US figures. Lewis Lukens, acting US ambassador to the UK, said: 'I commend the strong leadership of the mayor of London as he leads the city forward after this heinous attack.'

New York mayor Bill de Blasio added: 'Mayor Sadiq Khan is doing an extraordinary job … President Trump's attack on him is unacceptable.'

Mr Khan last night dismissed the President's criticism, saying: 'I've been busy dealing with the terrorist incident – I haven't got time to deal with tweets from Donald Trump.'

A White House spokesman said it was 'utterly ridiculous' to suggest the President had targeted Mr Khan because he is a Muslim and denied Mr Trump was 'picking a fight'.

She added: 'The President has been extremely clear that we stand in complete solidarity with the UK.'