Huge protests are expected in London for the first full day of Trump's visit, which will begin next Thursday night when he flies in from the Nato summit in Brussels.
His three day trip is thought likely to include a dinner with business figures at Blenheim Palace, meeting the Queen at Windsor and talks with Theresa May at her country retreat in Chequers. Trump is also thought to be keen to play golf at his courses in Scotland.
The programme is being designed to ensure Trump avoids London and the expected angry protests. He cancelled a trip last year for fear of demonstrations.
Around 50,000 people are expected to march from the BBC building in Portland Place to Trafalgar Square as part of the "Stop Trump" protest.
The group behind the balloon have raised more than £17,000 ($35,000) through a crowdfunding website to pay for the huge balloon and take it on a "world tour".
The group stated: "If we can troll Donald from the skies wherever he goes for long enough, he'll start seeing 'TrumpBaby' in his dreams."
The prospect of huge protests is not the only event already overshadowing Trump's visit to the UK.
Around 150 business chiefs have been invited to attend the black-tie gathering in Oxfordshire, which will be hosted by May.
But several have turned down the opportunity to come along to the event, the Financial Times revealed this afternoon
They include lastminute.com co-founder Baroness Lane-Fox, who said: "I understand why the government have to entertain Trump but I certainly don't want to."
Khan and the American leader have engaged in a long-running war of words over issues like crime and terrorism.
The row between the pair began last June when the US President accused Mr Khan of having a "pathetic" response to the London Bridge terror attack.
The balloon is 6m high. Photo / via Crowdfunder
Protesters will be able to fly their 'Trump baby' balloon above Parliament during his visit after permission was given by City Hall. Photo / via Crowdfunder
He tweeted: "At least 7 dead and 48 wounded in terror attack," the president wrote on his personal Twitter account, "and Mayor of London says there is 'no reason to be alarmed!'"
But critics pointed out that the London Mayor was saying residents should not be alarmed at the increased police presence - not at the terrorists.
Speaking about Trump's visit earlier this year, Khan said: "I think there will be protests, I speak to Londoners every day of the week and I think they will use the rights they have to express their freedom of speech.
"But they must be peaceful, they must be lawful."
He added: "As the Mayor of London it's probably inappropriate for me to join a protest when foreign leaders come into the UK.
"It's important though for me not to be scared to express my views about some of the things he's said.
"It's ironic that the architect of the hostile environment policy in this country has invited the architect of the hostile environment policy in the USA to London."
More than 10,000 people signed a petition calling for the "Trump Baby" inflatable to be given permission to fly, activists said.
Speaking about the balloon decision today, activist Leo Murray said: "We didn't get off to the best start with the Mayor's office over this, who originally told us that they didn't recognise Trump Baby as legitimate protest.
"But, following a huge groundswell of public support for our plan, it looks like City Hall has rediscovered its sense of humour. Trump Baby will fly."
A spokesman for the Nona Hurkmans group, which is behind the protest, said: "We are just a small group of friends who set out to use humour to take a stand against the rise of racist and fascist politics both here in the UK and over in the US.
"We have been genuinely overwhelmed and touched by the incredible levels of support we have received for our project."
Everything you need to know about Trump's UK visit
Donald Trump will finally fly into the UK for his first visit as US President next week.
Trump will arrive in Britain on Thursday night following a high stakes Nato summit in Brussels at which EU allies fear he could threaten the alliance.
A major row over defence spending could overshadow his visit to the UK.
Once he reaches Britain, he is expected to stay for three days for a "working" visit.
The trip is not the full State Visit Theresa May offered last year but he is expected to meet the Queen. Because it is a working trip, he is covering his own costs - though Britain will spend millions on security.
Why did Trump cancel his UK visit in February 2017?
Theresa May first invited Trump to the UK after she visited him days after his inauguration, becoming the first foreign leader to see the new President and Scotland Yard Chief Sir Bernard Hogan-Howe let slip that Trump would be visiting in June,
President Donald Trump will visit the UK next week. Photo / AP
In February 2017, it was revealed that Trump had decided to delay the visit amid snubs from MPs and in order to avoid protests. In addition to this, the trip was again postponed because of widespread dismay of his travel ban on citizens from Muslim-majority countries.
Trump was also due to come to the UK in February of this year to open the new US embassy, but a poll revealed that 4 per cent of people, around two million, said they would join a protest if he was given a full state visit.
Is Melania coming to the UK with Trump?
It is expected that the First Lady will join her husband in the UK.
Will Trump meet the Queen?
Windsor Castle is set to be closed to the public on July 13, suggesting that this is when Trump will meet the Queen, but details have not been confirmed. Ambassador Woody Johnson told Sky: "Yes, yes, I mean he has to see the head of state.
"Putting his foot on British soil, it's job one, it's very important, very symbolic. Meeting Her Majesty is the most important thing, because she's the head of state, and from then on, it'll be what the president wants to do."
The Coldstream Guards, the oldest regiment in the British Army, are also rumoured to honour the Trumps on their arrival but Buckingham Palace has not confirmed the arrangements.
What will Trump discuss with Theresa May?
Trade tariffs are expected to be the most discussed topic during Trump's visit to the UK, especially after a call with the President left Theresa May branding his decision "unjustified".
A statement released after this phone call said: "The prime minister raised the US decision to apply tariff to EU steel and aluminium imports, which she said was unjustified and deeply disappointing.
"The prime minister said the US, UK and EU are close national security allies and we recognise the importance of the values of open and fair trade across the world. The prime minister also underlined the need to safeguard jobs that would potentially be affected by the decision."
May and Trump are also thought to talk about the President's border policy after the Prime Minister said that the policy was "inhumane". May told MPs in the Commons last week that "when we disagree with the United States, we tell them so."
"But we also have key shared interests. It is right that we are able to sit down and discuss those with the president - a president of a country with which we will continue to have a long-standing special relationship."
Will Trump play golf on his UK visit?
Trump may spend a couple of days at the end of his visit at one of his golf courses in Scotland or the Trump International Golf Links in Aberdeen. However, this decision has not been welcomed by the country's politicians.
Scotland has told the UK government that it should foot the president's £5 million ($9.7m) security bill if the President should choose to visit a golf course, before he travels to Helsinki to see the Russian president Vladimir Putin.
Scotland's Justice Secretary Humza Yousaf wrote to UK Home Secretary Sajid Javid and said that the country does not want to settle the bill. He tweeted: "He is coming as a guest as the UK government, they must not leave Police Scotland with a £5m bill."
Trump's next visit has been planned for the 75th anniversary of VE Day in May 2020. Speculation also suggests that Trump will be in the UK for when Britain officially leaves the EU on March 29, 2019.
