Leeds United's ownership saga has almost come to an end after the Dubai-based investment firm GFH Capital signed a deal to purchase 100% of the club for £44m.

GFH Capital, a subsidiary of Bahrain's investment bank Gulf Finance House, is expected to complete the takeover in December after a one-month transitional period. If it gains the expected approval of the Football League, GFHC will be the 100% shareholder.

The current Leeds chairman, Ken Bates, will remain in his position until the end of the season before becoming an honorary life president, with no controlling authority. David Haigh, the GFH Capital chief executive and Leeds supporter, will join the club's board with immediate effect and the executives Hisham Alrayes and Salem Patel will be appointed in December.

Bates, 80, claims the deal will be formally completed on 21 December, although that specific date has not been confirmed by GFHC. "We have now completed all the negotiations and investigations with GFH and we've now completed the first part of the purchase and that happened at 10.30pm last [Tuesday] night," Bates told Yorkshire Radio.

"Quite simply they will be providing additional working capital for the club and they are also providing funds to strengthen the team. In fact there's already been a small injection this morning as far as working capital is concerned.

"Nothing has changed, I will continue as chairman until the end of the season when I look forward to handing over to my successor and become president and sitting back perhaps, taking a bit more time off and enjoying what has been eight years of very hard work."

Haigh added: "After a long process of negotiations, spanning Leeds, London, Monaco, Dubai and Bahrain, it gives us great pride today, to have completed the deal for Leeds United."

Bates purchased a 50% stake in Leeds in 2005 before the club entered administration in May 2007 and was relegated to League One. Last year he became the club's new owner, buying a 72.85% stake from an anonymous party.

Leeds have struggled in the Championship this season and have not won a league match in eight games. Their manager, Neil Warnock, has repeatedly spoken of his frustration that the takeover has taken so long to complete, but he expects to receive £8m to spend during the January transfer window.

The prospective new owners have not yet purchased either Elland Road or the training ground Thorp Arch, although will be looking to do so as a priority. Leeds are currently paying high rent costs on the stadium, which is owned by Teak Trading Corporation of the British Virgin Islands, while Thorp Arch is owned by the Manchester businessman Jacob Adler.

Leeds were relegated from the Premier League in 2004 but the Leeds United Supporters' Trust hope renewed ambition will soon see the club return to the top flight. However, the trust is disappointed that Bates will stay on.

Their chairman, Gary Cooper, said: "We've had six hard months of not knowing what the hell's going to happen to our club, watching attendances dwindle and performances on the pitch go off the boil.

"I'm sure it's just a title gesture but Mr Bates has been a divisive figure among the fans for a long, long time now. He's a really powerful character and supporters were hoping he would say goodbye. But let's look to the positives and move forward.

"There is a bit of doubt because there's a one-month transitional period where anything could happen. I'm going to reserve judgement until that month period is up and we actually do have new owners. Technically speaking, at this moment in time we don't."

Eurofin Capital, a private investment firm based in London and Lausanne, has been appointed by Leeds as financial advisors throughout the sale. Their director, Andrew Umbers, said: "We are delighted to have been involved in this transaction. Creating the right legacy to build on the prudent stewardship of Ken Bates was always one of our chief objectives and we believe that GFH provides this."