“While an important and prominent late-medieval house, its interest lies not
just in its architecture but in its historical association with the Cressett
family who were significant members of the royal court for many centuries,”
its English Heritage listing reads.

George Osborne imposed VAT on the renovations of listed buildings in the 2012
“omnishambles” budget, with the Treasury arguing it was an anomaly that
allowed the owners of manor houses to install swimming pools without paying
tax. It was later amended to exclude church buildings.

Mr Cash revealed he joined Ukip, to the fury of his father, because of the
burden of tax imposed on the “restoration classes”. It is leaving Britain’s
historic properties “crumbling away”.

“Our planning and tax policies should support, not discriminate against, the
rich heritage of our built inheritance and the efforts of those who enjoy
preserving it and sharing its custody with others and for future
generations,” Mr Cash said.

^{Chilham Castle, which is owned by Stuart Wheeler (ALAMY)}

A Ukip spokesman said the tax cut would help thatchers, stone masons and
carpenters, and said many owners of listed properties are not wealthy.

He said Mr Cash was open about his link to Upton Cressett, owned in a family
trust. “If we get to a situation where people who have an interest in a
subject can’t talk about it then you will be in a parlous state. No soldier
can talk about the defence budget and no scientist can talk about the
science budget.”

John Mann, the Labour MP for Bassetlaw, said: “I’m not sure that White Van Man
is going to be happy with this policy. It’s let the cat out the bag about
who Ukip really want to represent.”

The policy will offer a potential benefit to some of Ukip’s biggest donors.

Crispin Odey, the City supremo who runs Odey Asset Management and who has
donated £26,000 to Ukip, is the owner of Eastbach Court, a Grade II listed
Georgian manor in Gloucestershire. Two years ago he applied for planning
permission to build a £150,000 chicken coup in the style of a Greek temple,
with a stone colonnade, anthemion ornaments, a cornice, pediment and frieze.

Stuart Wheeler, the spread betting tycoon who has given hundreds of thousands
of pounds to Ukip, is the owner of Chilham Castle, a magnificent Grade
1-listed Jacobean mansion in Kent. He bought the property, described as one
of the “finest country houses in England”, after selling £7 million of
shares in his City firm and renovated it over two years.

Paul Sykes, who has given £2.7 million to the party and who has pledged to
bankroll Ukip’s election campaign, lives in a Grade II listed country home
on the Studley Roger estate, North Yorkshire.

A Ukip spokesman said none of the donors knew about or asked for the policy.