Boris Johnson was accused of 'dog whistle racism' and likened to right-wing 'Tea Party' politicians in the US this morning after his attack on the 'part-Kenyan' Barack Obama.

The Mayor of London spoke out against the US President after he urged British voters to stay in the EU and mentioned his African ancestry as he criticised the decision to remove a bust of Sir Winston Churchill from the Oval Office shortly after Mr Obama entered the White House.

Mr Johnson - who is favourite to succeed David Cameron as Prime Minister - suggested the President got rid of the statue as a 'snub' to Britain's wartime prime minister and a 'symbol of the part-Kenyan President's ancestral dislike of the British empire'.

But Shadow Chancellor John McDonnell hit out at Mr Johnson and demanded he withdraw the controversial remarks.

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The Mayor of London (pictured outside his north London home this morning) spoke out against the US President after he urged British voters to stay in the EU and mentioned his African ancestry as he criticised the decision to remove a bust of Sir Winston Churchill from the Oval Office

He wrote on Twitter: 'Mask slips again. Boris part-Kenyan Obama comment is yet another example of dog whistle racism from senior Tories. He should withdraw it.'

This afternoon Mr Johnson defended his remarks and said he did not imply the US leader was anti-British.

Diane Abbott, Shadow International Development Secretary, hit out at Mr Johnson, describing his remarks as 'offensive' and said they echoed those of the Tea Party's right-wing, anti-immigration tendency in the US.

Former Lib Dem leader Lord Campbell said Mr Johnson's comments were 'an unacceptable smear'.

'Many people will find Boris Johnson's loaded attack on President Obama's sincerity deeply offensive,' Lord Campbell said.

'If this is an illustration of the kind of diplomacy that we might expect from a Johnson leadership of the Tory Party then heaven help us.'

Boris Johnson (left) suggested the US President (pictured left arriving in the UK last night) got rid of the Sir Winston Churchill statue as a 'snub' to Britain's wartime prime minister and a 'symbol of the part-Kenyan President's ancestral dislike of the British empire'

Shadow Chancellor John McDonnell hit out at Mr Johnson and demanded he withdraw the controversial remarks

Referring to the removal of Sir Winston's bust, Mr Johnson wrote in The Sun today : 'No one was sure whether the President had himself been involved in the decision,' he said.

'Some said it was a snub to Britain. Some said it was a symbol of the part-Kenyan President's ancestral dislike of the British empire - of which Churchill had been such a fervent defender.'

Asked later today if he intended to imply Mr Obama was anti-British, Mr Johnson said: 'Not at all, not at all.'

Speaking outside a Subway restaurant in his Uxbridge constituency, he added: 'Well I think obviously people will make of the article what they want.

OBAMA'S KENYA CONNECTION Barack Obama, 10, and his father, also named Barack Obama, who married at least three times The president's father, also named Barack Obama, is a Kenyan native. According to the younger Obama's memoir Dreams from My Father, Barack Obama Sr. met his mother Ann Dunham while attending college in Hawaii. The couple divorced after three years of marriage in 1964, and the president saw his father just one more time after that before his death in a car accident in 1982. The president's first known trip to Kenya, as detailed in his book, was in 1988, when he spent five weeks there. He returned to Kenya in 1992 with Michelle, then his fiance, and again in 2006 during his first year in the U.S. Senate. Mr Obama made his first visit to Kenya as US President last year when he flew to the east African country for the Entrepreneurship Summit. Advertisement

'The crucial point is that I'm a big fan of Barack Obama - I was one of the first people to come out in favour of him ages ago.

'But I think there's a weird paradox when the President of the Unites States, a country that would never dream of sharing its sovereignty over anything, instructs or urges us politely to get more embedded in the EU, which is already making 60% of our laws.

'I think the issue really is about democracy - America guards its democracy very jealously and I think we should be entitled to do so as well.'

Downing Street said Mr Johnson was recycling 'false' claims in referring to the bust.

Ukip leader Nigel Farage backed up Mr Johnson's claims.

He told The Guardian: 'Look, I know his family's background. Kenya. Colonialism. There is clearly something going on there.

'It's just that you know people emerge from colonialism with different views of the British. Some thought that they were really rather benign and rather good, and others saw them as foreign invaders.

'Obama's family come from that second school of thought and it hasn't quite left him yet.'

The White House has previously insisted there was no basis to suggestions that the removal of Sir Winston's statue was influenced by Mr Obama's views on colonialism.

Responding to Mr Johnson's controversial remarks, Ms Abbott said: 'Boris dismissing president Obama as 'half-Kenyan' reflects the worst Tea Party rhetoric'.

Mr Johnson's attack on the President came after Mr Obama's controversial decision to make a major intervention in the EU referendum campaign.

He wrote a lengthy article in the Daily Telegraph this morning setting out the case for Britain remaining in the EU.

He pleaded with British voters not to cut ties with Brussels - saying it 'magnified' the UK's influence in the world.

He also invoked the spirit of the Second World War by claiming the sacrifice of GIs meant America has a stake in the EU debate and said our decision in June's referendum 'will echo in the prospects of today's generation of Americans as well'.

But a furious Mr Johnson responded by saying: 'It is deeply anti-democratic - and much as I admire the United States, and much as I respect the President, I believe he must admit that his country would not dream of embroiling itself in anything of the kind.

'It is incoherent. It is inconsistent, and yes it is downright hypocritical. The Americans would never contemplate anything like the EU, for themselves or for their neighbours in their own hemisphere. Why should they think it right for us?'

His anger was echoed by a string of senior Eurosceptic MPs who vented their fury at David Cameron and Defence Secretary Michael Fallon over a warning that there would be celebrations by Moscow and the Islamic State 'in Raqqa' if the UK voted for Brexit.

Justice minister Dominic Raab said President Obama was guilty of 'double standards' because he would 'not dream of opening the US border and allowing free movement with Mexico and he would not dream of allowing the US constitution to be trumped by a Latin American court'.

President Barack Obama and his wife Michelle met Queen Elizabeth and Prince Phillip at Windsor Castle for lunch today

The US President left the American Ambassadors residence in the Beast (pictured) this morning as he made his way to Windsor Castle to meet the Queen

And he mimicked the US President by adding: 'Can Britain do better outside the EU? I would have to quote Mr Obama in saying 'Yes we can'.'

But Peter Westmacott, Britain's former ambassador to the United States, hit back at the charges of hypocrisy. 'No one is asking the UK to surrender anything it's got,' he told the BBC this morning.

'What the President is saying is not telling people how they should vote; he is saying we are in a very important place as a member of the EU and we should think very carefully on turning our back on that.'

Number 10 and the White House have orchestrated a pro-EU blitz to coincide with the US President's visit.

Mr Obama said a vote to cut ties with Brussels will leave Britain less able to tackle terrorism, the migration crisis and economic difficulties.

And he said Britain and America's 'special relationship was forged as we spilled blood together on the battlefield'.

OBAMA'S GIANT FAMILY: HOW US PRESIDENT HAS RELATIVES ALL OVER THE WORLD - MAINLY BECAUSE OF HIS PHILANDERING FATHER A family together: Barack Obama (back row, second left) with Granny Sarah (front, second right) in 1988 Barack Obama's giant family stretched across America, Europe and Africa, in large part because of his father. Barack Obama Sr married at least three times - four according to some people - and had at least seven children. And he was such a brazen womaniser he even bought mistresses home when his latest wife was asleep, loudly demanding the marital bed for his conquests. Little wonder he turned out such a disappointment to the boy who, against all odds, went on to become President of the United States. But one became leader of the free world, the other ended up crippled in car accidents caused by drink-driving and corroded by jealousy. Obama senior married Stanley Ann Dunham, a white student from Kansas and the president's late mother, at a time when interracial marriages were still illegal in many parts of the U.S. President Obama's mother met his father at a Russian language class at the University of Hawaii in 1960. At the time he was the first and only African student at the university. When they married, she did not realise that he had a wife and child in Kenya. He married Kezia Aoko in a tribal ceremony and had two children, Malik and Auma. Barack Sr and Ms Dunham divorced in 1963 and Ann Dunham struggled as a single mother to bring up her child, just as her estranged husband was at studying at Harvard and reportedly carousing after women. At the university he met Ruth Bake and they married in 1964 and had two sons, Mark and David. But seven years later they split up and divorced. He then reconnected with his first wife Kezia and they are believed to have had two more sons. The President was raised with help from his grandfather, a soldier, and grandmother who worked in a bank. The last time he saw his father was in 1971 when he was ten years old. Obama Sr was killed 11 years later in a car accident in 1982. Of his early childhood, President Obama has said: 'That my father looked nothing like the people around me - that he was black as pitch, my mother white as milk - barely registered in my mind.' Advertisement

After meeting the Queen at Windsor Castle for lunch to celebrate Her Majesty's 90th birthday, Mr Obama will travel to Whitehall for meetings with government ministers, but none of them will disagree with his EU referendum intervention referendum.

Despite the Government and Conservative Party being deeply split over Brexit, all the senior ministers invited by David Cameron to take part in the hour-long bilateral meeting back continued EU membership.

On the guest list are all the holders of the so-called 'great offices of state' with Chancellor George Osborne, Home Secretary Theresa May, Foreign Secretary Philip Hammond and Defence Secretary Philip Hammond.

Not expected to be at the meeting are Northern Ireland Secretary Theresa Villiers - who might be expected to raise the continued support of the US for the peace process - or Justice Secretary Michael Gove, who has responsibility for some aspects of international justice policy.

Barack Obama has met David Cameron and his senior ministers in Downing Street before, five years ago in 2011. Today he will face senior ministers - all of whom support the EU

Mr Cameron will have a brief private meeting with the President accompanied just by key aides before the main bilateral meeting begins.

Topics expected to be under discussion include the battle against ISIS in Iraq and Syria, the continued instability in Libya and the migration crisis in Europe.

The two leaders will continue their talks at a meeting of the G5 group in Germany on Monday when German Chancellor Angela Merkel, French President Francois Hollande and Italian Premier Matteo Renzi will meet.

Responding to Boris Johnson's remarks Sir Stephen Wall, former British Permanent Representative to the European Union, said: 'Boris Johnson's comment implying the President of the United States is driven by his ancestral dislike of the British empire is demeaning to the debate. Using that type of language does not reflect Britain's standing in the world or the country we aspire to be.