The house had been put up for double the market value

The house at 21 Mivart Street in Easton, Bristol, was being sold for offers in excess of �160,000.

Three sealed bids are currently being considered by the owner in Devon.

However, the offers are not legally binding as the art by the cult graffiti artist was the item up for sale - with the house thrown in for free.

The free-painted artwork on the side of the terraced property, and accessible from the street, is believed to be one of the artist's early pieces, dating to around 2002.

The house and the mural are being sold as a package

It was daubed with red paint sometime between Wednesday evening and Thursday morning.

Estate agents Ocean were due to go to the property on Friday morning to see the damage before informing the seller.

Those people who submitted bids will then have to be informed so that they can make a decision whether or not to withdraw from the sale.

Vendor Sarah Anslow, of the Red Propeller art gallery in Devon, put the mural and house up for sale in February.

"We've been absolutely overwhelmed by the interest in this piece," she said, adding that having decided to sell the property it was important the work of art was kept "as it is".

Banksy's art has become very desirable among fashionable collectors with Angelina Jolie and Christina Aguilera among those who are reported to have bought his work.

But it's not the first time one of his murals has been defaced.

Mural stolen

Workers on the London Underground painted over a Pulp Fiction inspired piece earlier this month after mistaking it for ordinary graffiti.

And in March, a mural in east London was almost entirely removed by thieves.

One of Banksy's early murals was mistakenly painted over in the same month by Bristol council's graffiti-removal contractors.

And in February two smaller works in London were also painted over.