Asad Rehman, 51, one of the organizers of a massive protest planned for central London, said that among the motivations behind the protest was to show solidarity with Americans across the Atlantic who also oppose Trump.
May's "business-friendly" Brexit proposal was agreed by her cabinet only last Friday after two years of wrangling since Britons voted to leave the bloc in a 2016 referendum, though some supporters of Brexit cast it as a betrayal.
Rarely has a foreign leader been so mocked on an official visit - London's mayor, a Muslim who has challenged Mr. Trump's world view - okayed the balloon, which is an apt symbol of Mr. Trump's tempestuous relationship with Britain, traditionally the United States' closest ally.
There is more to the 20-feet high balloon caricature - which depicts the leader as an angry infant wearing a nappy and clutching a mobile phone - than mockery, demonstrator Sheila Menon said.
The U.S. Embassy has even warned American citizens to keep a low profile during the visit because of the planned protests - the sort of warning usually issued in more volatile locations.
The Trumps arrived at Stansted Airport near London on Air Force One earlier that afternoon for the controversial trip to Britain.
"But from the public, the welcome will be far from warm", he added saying there would be protests across the country against Trump's "abysmal record on human rights, his repugnant attitude towards women and his disgusting treatment of minorities".
Trump did not call Putin a friend or foe but referred to him as a "competitor".
Russian spacecraft completes fastest-ever orbital rendezvous with International Space Station
Progress 70 will stay linked to the space station until January 2019, when it will be discarded, NASA officials said. In February, a Progress MS-07 launch was cancelled at the last minute after another attempt in October 2016.
It has also complained that 300 officers working during the visit will have to sleep on camp beds in a gymnasium that has no hot water and restricted access to hot food. "We have come to an agreement which absolutely delivers what people voted for", she said in a statement.
A YouGov poll released on Wednesday found that 77 percent of respondents had an unfavorable opinion of Trump and just 50 percent thought his visit should have gone ahead.
A campaign is also underway to get "American Idiot", a 2004 song by the U.S. punk rock band Green Day, to the top of the UK Singles Chart.
But Owen Jones, a left-wing journalist and lead organiser of Britain's "Stop Trump" protests, disagreed.
Along with trade and security ties, Downing Street said the other key areas to be discussed between the two leaders included Brexit and the Middle East.
Prime Minister Theresa May will host Mr Trump and his wife Melania at a dinner at Blenheim Palace this evening.
Perhaps in a reference to Mr Trump's meeting with Vladimir Putin on Monday, she said that Britain and the U.S. work closely together in the interests of their shared security, "whether through targeting Daesh [Islamic State group] terrorists or standing up to Russian aggression".
The Trumps trip to the United Kingdom is not an official state visit, however, tomorrow the couple will visit the Sandhurst military academy and hold talks at May's country house, Chequers.