The stadium is on the site of the old Leckwith athletics arena

Developers said that all finances were in place and that the project was now guaranteed to be completed.

Meanwhile, Marks and Spencer has been unveiled as the latest store to take a place in the retail park.

Alongside the 30,000-seater football stadium, an athletics venue and a multipurpose sports facility will also be built at the 60-acre Leckwith site.

It is hoped the football stadium will be ready by early 2009.

Cardiff's City's old Ninian Park site had been sold for £9m to Redrow Homes, while a further £12m has come from Cardiff City football club and another £2m from a Football Trust Grant.

Work on clearing the site began earlier in 2007

Marks and Spencer has joined Costco, Asda and JJB in taking space in the Capital Retail Park, which means that more than 75% of the £42.5m site has been let.

Cardiff Council leader Rodney Berman said he was delighted that the details of the development had all been agreed.

"Now that all the legal formalities are out of the way we're going to see things take shape very quickly over the coming months," he said.

This is an historic day in the club's history and is a new beginning Peter Ridsdale, Cardiff City FC chairman

He added that work had already started on the site of the new athletics stadium, where the running track will soon be laid.

Cardiff City's chairman Peter Ridsdale said that "any lingering uncertainty" about the project had now been taken away, after backers had "overcome insurmountable obstacles".

"I am absolutely delighted that after many false dawns but much hard work, our new stadium project has now gone unconditional," he said.

"This is an historic day in the club's history and is a new beginning that will hopefully provide the springboard to us also being able to deliver Premiership football to the city of Cardiff."

The development means that the main contractor for the football stadium Laing O'Rourke can get its machinery on site to start work.