Ineos, who will assume delegated responsibility for the club's football operations, and United have entered an agreement under which he will acquire 25 per cent of the club while investing $US300 million ($A440 million) into Old Trafford the club stadium which now looks very dated..
"As part of the transaction, Ineos has accepted a request by the board to be delegated responsibility for the management of the club's football operations," a club statement said. "This will include all aspects of the men's and women's football operations and academies, alongside two seats on the Manchester United PLC board and the Manchester United Football Club boards.
"The joint ambition is to create a world-class football operation building on the club's many existing strengths, including the successful off-pitch performance that it continues to enjoy."
Manchester United fans have long wanted the owners, the US-based Glazer family, to sell up. (AP PHOTO)
Ratcliffe said: "As a local boy and a lifelong supporter of the club, I am very pleased that we have been able to agree a deal with the Manchester United board that delegates us management responsibility of the football operations of the club.
"While the commercial success of the club has ensured there have always been available funds to win trophies at the highest level, this potential has not been fully unlocked in recent times.
"We will bring the global knowledge, expertise and talent from the wider Ineos Sport group to help drive further improvement at the club, while also providing funds intended to enable future investment into Old Trafford."
Ineos already own Nice and Lausanne football clubs and the Ineos Grenadiers cycling team.
Old Trafford, while still England's largest club stadium, is in dire need of refurbishment. (EPA PHOTO)
Executive co-chairmen and directors Avram Glazer and Joel Glazer, said: "We are delighted to have agreed this deal with Sir Jim Ratcliffe and Ineos.
"Sir Jim and Ineos bring a wealth of commercial experience as well as significant financial commitment into the club."
The deal, which comes 13 months after the Glazers announced they would be open to selling part or all of the club, will fall short of a Christmas present for many United fans who have long campaigned for the US-based owners, who bought the club in 2005, to sell up completely.
This was evident in a statement from the Manchester United Supporters Trust who said: "Fans have very mixed feelings today. We welcome the investment from a boyhood red, Sir Jim Ratcliffe and his INEOS company, but many will wish his ownership stake was greater than the initially rumoured 25 per cent.
"We note the statements that he and his team will control sporting activities, yet puzzle how any organisation can put its very core business in the hands of a minority shareholder, and how that meaningfully works in practice."
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