John Brandler, owner of Brandler Galleries in Brentwood, Essex, spent “a six-figure sum” to buy the mural, which appeared on the corner of Rothesay Avenue in Lenton in October before being removed early on Wednesday morning.
The 65-year-old said the artwork, which shows a girl hula hooping with a bike tyre, had started to form mould within its protective plastic casing, and he plans to restore it and move it to a museum in Suffolk.
“If I hadn’t bought it and removed it, in two years’ time there wouldn’t have been a Banksy there at all,” he told the PA news agency.
“I appreciate the council were trying to protect it from vandals coming along but actually it was creating a death sentence for it.
“I am pleased I’ve been able to save it from destruction.”
Mr Brandler said he is paying thousands of pounds to send the artwork to Scotland where it will be restored.
The artwork will then be put on display in a museum in Bury St Edmunds, but Mr Brandler said the entire exhibition could return to Nottingham in the future.
“This isn’t a one-way street, work with me and it would be lovely to bring the whole show back,” he added.
Asked if he had a message for residents upset by the removal of the artwork, Mr Brandler said: “Somebody told me it belongs to the people of Nottingham – no, it belonged to the person whose wall it was on.
“From what I hear they offered it to a number of organisations in Nottingham and nobody was interested.
“It’s very easy to say ‘we must keep it’ – all right, you pay for it, you pay for the maintenance, the security, the insurance, the restoration.”
The Banksy is one of several Mr Brandler has purchased, including Season’s Greetings in Port Talbot, Wales.
Dan Golstein, a University of Nottingham student, said he was woken at around 6am on Wednesday to the sound of the Banksy piece and the wall it rests on being removed.
“In terms of how I feel as a local, I think it’s a real shame that they decided to sell,” the 21-year-old told PA.
“I understand why, but ultimately it was a treasure to the community and it’s sad that now what is left is wooden board and debris.
“It was installed at a really difficult time for Lenton residents due to high Covid rates, and it brought a lot of life.”
PA contacted representatives of Banksy for comment on the removal of the mural.