THE world of Banksy thrives on secrecy and subterfuge. The anonymous artist has put together one of the biggest art shows the city has ever seen, right under our noses, with hardly anyone knowing it was happening.

Here at the Evening Post, we were let into the secret on Wednesday afternoon, when we had a hush-hush visit from two of Banksy's PR people.

The bubbly pair giggled excitedly as they sat in the newspaper conference room, explaining to editor Mike Norton, deputy editor Rob Stokes and myself how Banksy wanted his home city's local newspaper to break the story.

At that time, just five people knew about it – including three senior managers at the venue.

The rest of the staff at Bristol's City Museum and Art Gallery were left in the dark about the plans until late on Thursday – they were told the museum had shut for two days so a film crew could come in to make a TV programme.

"I think we might have dragged them down to our level rather than being elevated to theirs," says Banksy, referring to the subterfuge employed by museum top brass to keep the event secret from city councillors and trustees.

"This is the first show I've ever done where taxpayers' money is being used to hang my pictures up rather than scrape them off," he adds, with typical irony.

Councillor Simon Cook, deputy leader of the council, who is also in charge of sports, culture, tourism and capital projects, is keen to point out that this isn't really the case.

"This show will bring in a vast amount of money to the local economy over the next three months, and it's cost the council nothing," he says. "It is entirely funded by Banksy."

The Bristol-born artist is mounting the show as a salute to the city which supported his early street art career.

"That meant putting up with a lot of mistakes that were made in public," Banksy says.

"But this show is my vision of the future, to which many people will obviously say – you should have gone to Specsavers."

But Simon Cook says he has been "totally blown away" by the show.

"I'm absolutely gobsmacked to see it," he says. "Totally blown away. The scale of the show is amazing. Banksy has taken over the entire museum.

"The international art world has known this show was coming for some time," he adds. "But nobody had any idea where it would be. I think most people assumed it would be in Los Angeles or New York, but for him to bring his work home to Bristol is a real coup for the city.

"It is a huge credit to the management at the museum who knew about the show but managed to keep it a secret – even from the city council."

Much of the museum has been rearranged to accommodate Banksy's work, with some of the collection taken into storage to make way.

Many items from the upstairs galleries remain, in order to set-off Banksy's humorous pieces of artistic pastiche to best effect.

Rebecca Burton, deputy head of Bristol Museums' collection and archive, says: "It's been an interesting few weeks, while we tried to organise this show without anyone knowing about it.

"But the amazing thing is we never actually got to meet Banksy – at least we don't think so. There were a few guys working on the exhibit for the last 36 hours, so any of them could have been Banksy. We'll never know which one."

Twelve of the museum staff only started two days ago – little realising why the venue might need so many extra members of summer staff.

"I thought it was just a summer job," says Dan Rankin, 20, of Braintree. "I can't believe my luck."

Tom Scott, 24, of Clifton, also started working as a gallery assistant just two days ago.

"I had a high-pressured sales job, which I didn't like much, so I packed it in," he explains. "I went down to the job centre, and they mentioned this position was available through the summer. So I thought, why not give it a go.

"On my first day I saw all the fossils and minerals and old paintings, and I wasn't sure how I was going to cope with the boredom for the next few months – then all this arrives on the scene. I certainly don't think we'll have time to be bored with all these visitors on their way."

What about the man himself? Will Banksy be wandering around his own exhibition in the next few weeks?

"It's highly unlikely," says his PR person Jo Brooks. "He spent much of Thursday at the museum, putting the finishing touches to the show. But then he made sure he made his escape before the opening party and media previews. As far as he's concerned he's done his bit now."