* UK firm forms INEOS Team GB to compete for America's Cup
* INEOS teams up with Ainslie in quest to win "Auld Mug"
* Commits to spend 110 million pounds to fund 2021 campaign (Adds INEOS to be sole sponsor)
By Alexander Smith
LONDON, April 26 (Reuters) - Ben Ainslie has secured 110 million pounds ($153 million) from British petrochemicals company INEOS to fund Britain's latest bid to win the America's Cup.
INEOS said it had formed INEOS Team GB with Ainslie, the most successful Olympic sailor, to compete for the "Auld Mug" and was committed to making the biggest ever America's Cup investment by a British challenger.
"We have a first-class team and will do everything we can to bring this trophy back to Britain where it belongs," Jim Ratcliffe, the billionaire founder and chairman of INEOS, said in a statement on Thursday.
Ainslie had been building his Land Rover BAR team to challenge holders Emirates Team New Zealand in Auckland in 2021, but told Reuters last month that he needed more funding to build a state-of-the art "foiling" monohull to take part.
"This is an amazing boost for British sport. With this significant commitment from INEOS to fully fund a two boat challenge," Ainslie said.
Under the arrangement, INEOS will be the only sponsor, meaning Ainslie has ended his partnership with Land Rover and other commercial sponsors. He will also no longer have support from private backers.
Ainslie told a news conference that his previous commercial partners were disappointed but had been "incredibly gracious".
INEOS Team GB will now represent the historic Royal Yacht Squadron's affiliated club, Royal Yacht Squadron Racing.
The America's Cup was first contested in 1851 at the Royal Yacht Squadron off the south coast of England, when 15 of its boats raced and lost to the U.S. yacht "America", which gave the oldest trophy in international sport its name.
Despite many attempts in the intervening 167 years, Britain has never won the Cup. Ainslie has made it his mission to "bring the Cup home", although his first attempt last year in Bermuda ended in disappointment when it was won by New Zealand.
The holders, who beat Oracle Team USA to lift the Cup, decided to switch from foiling catamarans, which "fly" on top of the water at extraordinary speeds, to 75-foot single-hulled craft which will also use hydrofoiling technology.
INEOS said Ainslie would skipper the racing yacht, with fellow British Olympic gold medallist Giles Scott its tactician.
Grant Simmer, who has won the America's Cup four times and was hired by Ainslie last year, will be CEO of INEOS Team GB and New Zealander Nick Holroyd, another recent hire by the 41-year-old Briton, will be its chief designer. ($1 = 0.7176 pounds)
Reporting by Alexander Smith Editing by Toby Davis