When Jeff Allen went to a wedding he asked a friend to give his beach hut a lick of paint.
But when he returned two days later he discovered his hut had been transformed into a psychedelic piece of art.
Mr Allen has now been given just two weeks to repaint it in strict Brighton and Hove City Council-approved colours.
The brightly decorated hut has caused a minor storm at Hove seafront since it was finished on Monday.
Scores of walkers have stopped for a picture with the unusual building that stands out from the rows of regulation green huts.
Today Mr Allen, from Southwick, who has owned the hut for seven years, said: “I wanted the beach hut to be painted and told the decorator he could paint the door in any colour.
“But obviously he got it wrong and painted it in every colour.
“The council have said I have to change it within two weeks.
“I think I have broken the 11th commandment – thou shalt not paint a beach hut in different colours than those specified. No one in a million years could get away with that.”
The council said new owners are given “clear terms and conditions” on beach hut to preserve the colour of the outside.
A council spokeswoman said: “We specify a particular shade of pale green for the roof and sides of the building, while the bottom sections are painted in a burgundy colour. Owners are given specific BS trade numbers for these two shades.
“The shade of green blends with the seascape beyond and preserves the view from the adjoining conservation areas.
“However, owners are encouraged to customise their huts by choosing any single colour they like for the front doors, and colours already chosen vary from sky blue to deep crimson.”