Britain's third richest man Sir Jim Ratcliffe wants to build luxury summer house on stilts at his £6m mansion

Britain's third richest man, Sir Jim Ratcliffe, has proposed building a luxury summer house at his £6m holiday home on stilts so it doesn't get flooded.

The petrochemicals magnate, who is worth an estimated £18bn, wants to erect the residence in the gardens of his sprawling estate in New Forest National Park.

His neighbours are unhappy with the plan to give him perfect views of the Hampshire coast, saying it will blight the landscape and "stick out like a sore thumb".

They also argued that the planning application should be rejected because the property could be deluged with water as the area is prone to flooding.

But Sir Jim, 67, has seemingly sidestepped that issue by pledging to position the house, made from oak and cedar shingles, on a raised platform supported by wooden posts so it doesn't get inundated.

Planning documents he has submitted read: "An ideal spot for relaxation, the isolated setting and scenic views are key qualities to the design of the summer house.

"The semi-open spaces intend to encourage occupants to enjoy the advantages of the great outdoors and living in the New Forest National Park, an area renowned for its picturesque countryside.

"Lifting the building floor height addresses the site's susceptibility to rising flood levels as a result of climate change."

The billionaire, who owns chemicals giant Ineos, previously fought a six-year battle with neighbours, planning authorities and conservationists to get his £6m mansion built.

After rejecting his application five times, national park planners eventually granted approval on the sixth attempt and builders began work last year.

Sir Jim, who relocated to Monaco in February, has also submitted another planning application for his New Forest estate.

He hopes to turn a derelict "tin cottage", which he bought for £2.5m in 2006, into a three-bedroom home to house a "permanent guardian" who would be responsible for maintaining the grounds.

It would include an open plan kitchen and dining area, two bathrooms, a lounge area and a cloakroom.

The businessman, who grew up on a council estate in Greater Manchester, got a 2:1 degree in chemical engineering at the University of Birmingham.

He only started his first business weeks before his 40th birthday and founded Ineos aged 45 in 1998.

The company's annual turnover is about £45 billion and it employs more than 18,500 people at 181 sites across 22 countries.

Its products are, among many other things, used to clean water, make toothpaste, manufacture antibiotics, insulate homes and package food.

Sir Jim saw his wealth increase by an astonishing £15.3 billion between 2017 and 2018.

He married his first wife Amanda Townson in 1985. The pair, who have two sons, divorced in 1995. He has a daughter with his second wife Alicia.