Developers Oak Holdings and Rotherham Council put pen to paper on the development agreement on Tuesday afternoon, allowing work to start on the £300million entertainment complex in the Rother Valley.

"We can now move confidently towards gaining tenant commitment," said Oak chief executive Steve Lewis. "Rotherham is just the supreme location. More than a million people within 30 minutes' drive, and half the UK population within two-and-a-half hours."

The 327-acre former coalfield site will become the largest covered entertainment and sports complex in Europe.

YES! is forecast to attract £350m of investment and create up to 3,000 jobs once complete.

Among its long list of attractions will be an Olympic-scale white-water kayaking course.

"This is a significant milestone in bringing the YES! Project from vision to reality," said Coun Roger Stone, Rotherham Council leader. "The development will boost not just the local but the regional economy."

"Together with other visitor destinations across South Yorkshire it will really put the area on the leisure, sport and entertainment map."

The agreement includes the terms for the 250-year lease of the development site. It follows last month's cabinet approval.

Work is expected to start around the end of this year, and be complete by 2012.