Councillors in Thurrock, Essex, were told Mrs Gorman and her husband had carried out unauthorised renovations destroying important features of the Tudor farmhouse in Orsett which is Grade II listed.
The councillors voted 8 to 1 to go ahead with court action over 33 alleged offences. Most carry a maximum penalty of £20,000 or six months' imprisonment.
In a report, members of the planning committee were told the Gormans had been advised to stop work when the scale of their alterations were discovered, but had continued.
The report said: "There appears to have been some concept to create a pseudo-medieval building. Unfortunately the changes are pure invention, not historically correct, and detract considerably from the original form and detail of the house.''
Mrs Gorman, the MP for Billericay, and her husband will also be ordered to restore the farmhouse to as near original condition as possible.
If they refuse, the council will do the work and charge them for it.
The only dissenting voice came from a Tory councillor, Ray Andrews. He called for a deferment "to let members look at all the implications".Reuse content