A farmer built an entire mock castle behind a screen of hay bales and lived there concealed for four years to evade planning regulations, officials said on Friday -- but it may be torn down anyway.

Robert Fidler hopes to take advantage of a provision of planning law that allows buildings without planning permission to be declared legal if no objections have been made after four years
But Reigate and Banstead Borough Council in Surrey is not impressed.

"It does not count because the property was hidden behind hay bales," said a spokeswoman. "No one knew it was there."

The council wants the building near Redhill some 30 km south of London to be demolished, along with an associated conservatory, marquee structure, wooden bridge, patio, decking and tarmac racecourse.

"It looks like a mock-Tudor house from the front and it's got two turrets at the back," the spokeswoman said. "I understand there is also a cannon."

The couple would have been unlikely to get planning permission as the farm was in "green belt" land where building was restricted, she said. A hearing takes place in February.

Fidler's wife Linda told the Daily Mail newspaper the children grew up looking at straw out of the windows of the house and that they kept their son away from playschool on the day his class were due to do paintings of their houses.

"We couldn't have him drawing a big blue haystack," she said. "People might ask questions."

Planning inspectors had been called to the site by concerned neighbours shortly before Fidler took the hay bales down in summer 2006 but had not seen the house.

"When the inspectors went there, all they saw was hay bales and hay bales on agricultural land are not that unusual," the spokeswoman said.

"I think the neighbours thought there might be something going on but it is difficult to tell, isn't it?"