A villager says the peace he used to enjoy in his garden has been shattered by what he describes as a “growling exhaust noise” from a diesel generator.

It has been installed at a bistro reopened by the multimillionaire owners of Lympne Castle, near Hythe.

Bosses say the temporary generator only emits a “very small hum” and will soon be replaced by a new electrical substation.

A spokesperson said: “We speak above 55 decibels. A bird chirps at 66 decibels. The generator itself from the neighbour’s house measures 38 decibels.”

But neighbour Ian Brown, who has lived in Lympne for the past nine years, has been increasingly frustrated by the noise.

The 80-year-old said: “Why in God’s name do they need a generator? I just can’t understand why they need it.

“The machine’s growling exhaust noise has destroyed the peaceful conditions in my garden and prevents or disturbs sleep unless windows are kept closed.

“It’s alright today when the wind’s up, but on still days, I can’t use my garden from the constant droning.

Businesswoman Dr Ann Kaplan Mulholland - star of reality TV show The Real Housewives of Toronto - and her husband, Dr Stephen Mulholland, bought the castle for £5.5 million in 2023

They have since invested in regenerating the Grade I-listed building and its grounds, including reopening its bistro in August, renamed The Naughty Dog.

A retrospective application for works to the eatery - including modernising the site to house a new professional kitchen - was approved by Folkestone and Hythe District Council earlier this year.

But another resident, Lynn Frank, was frustrated planing permission had not been secured before the works took place.

“And there was no notice that this was going to happen. It’s incredibly irritating.”

She wrote on the council’s planning portal: “This is one of many applications that should have been put in for the extensive works.

“The owner of the castle was well aware of planning permission rules. This work was done in blatant disregard for the council planning permissions.”

Council officers noted two objections had been lodged and their report said: “While it is regrettable that planning permission wasn’t secure pre-commencement, the fact the application is retrospective is not a material planning consideration.

“The immediate neighbour has objected because of noise and disturbance from a generator. The objection is understood, but this is not part of the current application.

“Officers have informed the agent that permission will be required if the generator is to remain and that noise and acoustic shielding will need to be considered.”

A castle spokesperson told KentOnline the “silent generator” is housed in an enclosed structure behind a stone wall.

“If standing right next to it, there may be a very small ‘hum’, similar to if you had an AC unit on in your home,” they said.

“The silent generator services the castle restaurant until 6pm each day, so it wouldn’t disrupt sleep.”

"The backyard adjacent to the castle property is, in fact, castle land. Part of it, adjacent to this person's house, is their land.

“There is no boundary line in this yard as we have left it "as is" for their aesthetic enjoyment.

“The neighbour's backyard is aside his house where he has dug up land to plant a future garden on part of our land.

“We will be putting a wall up and have respectfully consulted with him as to what type of wall he would like.

They added: “A new electrical substation will be installed in the spring to replace the generator.

“Castle management purchased a silent generator with due respect for the neighbourhood, taking great effort to make sure we are considerate to the local community.”

Find out about planning applications that affect you by visiting the Public Notice Portal.

The castle’s owners previously apologised for a ”miscommunication of the site’s boundaries” after production vehicles parked on a private road and in the nearby village car park while filming for a comedy was taking place.

This week, Dr Kaplan Mulholland announced she would be moving to Milan to avoid paying more taxes in the UK under changes the government is making to non-dom rules.

But the couple will not be selling the castle. A documentary following their renovations of the site is currently being filmed.

A picture of Mr Brown has been removed from this article after representatives for Lympne Castle said it had been taken on the castle's land.