British sailing great Sir Ben Ainslie has found the funds to to make a potent challenge for the America's Cup in 2021.

Sir Ben Ainslie's British challenge for the America's Cup has received a huge boost with a new $217m sponsorship.

The staggering amount of money comes from Ineos, Britain's biggest privately owned company which has grown into one of the world's top 10 petrochemicals businesses by leasing or buying unwanted assets from firms such as BP and ICI.

It was founded by billionaire pro-Brexit businessman Jim Ratcliffe and, according to The Guardian, is one of the main UK exponents of fracking, a controversial process of drilling down into the earth before a high-pressure water mixture is directed at the rock to release the gas inside.

GETTY IMAGES Sir Ben Ainslie was a star of the America's Cup World Series in the buildup to Bermuda.

The British sailing syndicate is a confirmed challenger for the next America's Cup in Auckland in 2021 after they were beaten by Emirates Team New Zealand in the challenger semifinals in Bermuda last year.

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The major British development comes as speculation increases over a potential second US challenge to complement the return of the New York Yacht Club. Sailing Illustrated reported that the second American team had already raised some starting funding and had serious intentions.

SUPPLIED Ben Ainslie Racing's challenge for the America's Cup in Bermuda came up disappointingly short.

But they were still well off the levels that Ainslie will now enjoy.

"With the skill of Sir Ben Ainslie and his team, I think Ineos Team GB has a great chance of success in 2021 and I'm looking forward to the challenge," Ratcliffe, a keen sailor whose other sporting interests include owning a Swiss football team, said.

Ainslie said the new class rule announced by Team New Zealand for the radical 75-foot foiling monohulls brought a realisation that he needed to upscale his challenge and build two boats - one to race in the initial America's Cup World Series and then an improved design for the actual America's Cup in Auckland.

"We knew the concept of the boat was pretty extreme, but getting the class rule we had a realisation that we would need to build a second boat and the costs of building a second boat would have taken the budget up by about 30 per cent," Ainslie told The Times.

The greatest challenge in sport! INEOS Team GB will use the very best of British technology to design and build two AC75s, 75 ft foiling mono-hulls to compete in the 36th America's Cup in 2021 #americascup pic.twitter.com/X80lFY0Hul — INEOS Team GB (@INEOSTeamGB) April 26, 2018

The mega-deal is another sign of the seriousness challengers are taking to try to wrestle the Cup away from Team New Zealand. Challenger of record Luna Rossa has a massive sponsorship deal with Italian fashion house Prada that pr5omises to make them competitive.

Ratcliffe said an accidental meeting with Ainslie had turned into a serious business and sporting deal.

"It turned into the most expensive gin and tonic I had ever had," Ratcliffe said in The Times.

"I didn't go to see Ben to talk about this, I went with a mutual friend to go for a drink. We got on quite well, the conversation naturally moved on to the America's Cup. He talked about where he was with the next campaign.

"Ben is the best sailor in the world and is a Brit, which is a pretty good starting point. But he wasn't fully funded for a two-boat strategy. And if you are not fully funded, you are not going to win the America's Cup."

Ratcliffe said that he would only fund the team as sole investor. That left Ainslie in the difficult position of dropping sponsors who had backed his challenge in Bermuda.

Ineos replace Land Rover as title sponsor in a move that has left the famous British carmaker disappointed.

"Land Rover was notified that Ineos had bought the team and that its contract was terminated," a statement from Land Rover said.

"We are extremely disappointed having worked tirelessly to support Ben and the entire team. It is a great blow to us all that our partnership will not continue.

"Land Rover remains committed to the sport of sailing. We wish Sir Ben and the British team every success in their campaign to bring the Cup home."