Could the owner of this derelict building, now adorned by a Banksy artwork, be sitting on a goldmine?

Past works by the mystery street artist have been sold for half a million pounds - and at least one was sold for more than a million.

Local people were been left stunned and delighted after the elusive stenciller crept into Dover and created a Brexit-themed image on a derelict building.

But it is not yet knowN what the property owners in London will do with the work of art.

Dovorian Brian Whiting said he and other townsfolk were glad to see it.

He said: “It’s absolutely stunning. We’re thrilled and it’s done Dover a great favour.

“That building has been derelict for a long time. This is an absolute improvement and I’m sure the owner will be thrilled with it.”

The huge Dover mural appeared on the three-storey former Castle Amusements arcade in Townwall Street yesterday.

The image is on the flank wall facing York Street.

Video: A Banksy mural appeared in Dover

It signifies Brexit by showing a workman on a ladder chiselling off one of the 12 stars of the European Union flag.

Banksy confirmed it was his work by posting the image on his Instagram account.

It is in a highly conspicuous position near the port by a main roundabout.

On the other side of the building there is a “Welcome to Dover” sign.

Video: People react to mural

The town has played a symbolic and central role in the Brexit debate and last year’s referendum and has been the scene of violent clashes between far right and anti-fascist groups.

"I think it’s great for Dover. As soon as I heard about it I wanted to come down and see it for myself" - Natalie Fielding

The arrival of the latest Banksy marks a return to the south coast of Kent for the artist following his controversial Art Buff creation in Folkestone in 2014.

That resulted in a High Court battle over ownership between art charity The Creative Foundation and the tenants of the building, Dreamland Leisure.

The court ruled in favour of The Creative Foundation, meaning the piece could return to Folkestone after it had been removed during the dispute.

Today, local people were still turning up to the Dover image to view and photograph it.

It had already been spoiled by one small piece of graffiti saying “The Clash,” thought to refer to the iconic punk band.

The graffiti, written between two of the ladder rungs, did cause comments of dismay among Dovorians on social media.

Natalie Fielding, of St Margaret’s-at-Cliffe, said of the mural: “I think it’s great for Dover. As soon as I heard about it I wanted to come down and see it for myself.

“Banksy is an iconic street artist and and it’s great for Dover to have something like that here.

“The image is so important with what’s going on withe Brexit.

“I heard it was here yesterday afternoon through social media.”

Dawn Maddison of the Dover smART Project art group said: “We think it’s a great stimulating starting point for lots of our projects.

"It’s getting people interested in art and it’s a really important part of things to regenerate Dover.”

Charlie Elphicke, Dover MP from 2010, and now Conservative Parliamentary candidate, said on social media: “Loving the Banksy. Here at the Dover frontline we’ll keep chipping away to make a success of Brexit and be ready on Day One.”

A Banksy piece called Keep it Spotless was sold at auction in February 2008 for $1.7 million (now £1,313,709).

It showed a maid lifting wallpaper to shovel swept dust behind it.

In that same month a piece called Simple Intelligence Test, showing monkeys stacking safes, went for £550,000 at auction at Sotherby’s in London.

The 8ft tall Happy Shopper statue was sold for £420,000 at Phillips in London in February 2014.

KentOnline and the Dover Mercury have made attempts to trace the owner.

Dover District Council confirmed that it does not own the building and says that the graffiti is a matter for the owner to deal with.

A spokesman commented: “We are aware of the interest around the artwork attributed to Banksy that is displayed on the side of the former Castle Amusements building on Townwall Street.

“The building is not owned by Dover District Council but is within the Dover Waterfront area that is currently the subject of a master planning process, looking at a planning and regeneration framework for the future of the area.

“We welcome the interest that the artwork is generating for the town in the short term and are monitoring the situation.”

The council confirmed that it received no request for permission to do the work.

The Land Registry lists the building as currently owned by a company called Maudesley Limited of Stamford Hill in north London.

The land was bought by it in April 2007 at a cost of £420,000.