The new part-owners of Birmingham International Airport said they were looking forward to developing the facility after sealing the £420 million deal to buy just under half.

Airport Group Investments Ltd (AGIL) - a joint venture between the Ontario Teachers' Pension Plan and the Victorian Funds Management Corporation - now owns 48.25 per cent in the complex.

AGIL, which is owned 60.1 per cent by Teachers and 39.9 per cent by VFMC, bought the shares from Macquarie Airports Group and Aer Rianta.

The consortium is thought to have already allocated funding to pay for the runway extension at BIA which will enable direct flights to China and the west coast of the US.

The deal went through after the West Midlands District Councils - Birmingham, Dudley, Walsall, Sandwell, Wolverhampton, Coventry and Solihull - decided not to exert their pre-emption rights. The authorities, which together own 49 per cent of the airport, would have been able to buy the 48.25 per cent stake had they wanted to match AGIL's offer.

Staff, through an employee trust, own 2.75 per cent in the airport, which is the sixth largest in the UK and handles more than nine million passengers every year.

Jim Leech, senior vice president of Teachers Private Capital, said: "We look forward to working with VFMC, the district councils and other stakeholders to forge a long term profitable partnership that will see Birmingham airport reach its potential as Europe's leading regional airport."

Leo de Bever, chief investment officer at VFMC, said: "This is an exciting milestone for VFMC in its journey towards becoming a centre of investment excellence.

"This investment will be the cornerstone in a portfolio of direct infrastructure investments which we intend to build over the coming years.

"The airports plays a key role in enhancing economic growth in the West Midlands region and AGIL is an ideal long term partner for the district councils."

West Midlands District Councils welcomed Ontario Teachers' and Victorian Funds Management as new shareholders in Birmingham Airport.

The shareholders said they anticipated the runway extension, together with its associated infrastructure including a new international pier, would be completed by 2012. The shareholders intend to charge the management of Birmingham Airport with progressing the runway extension as expeditiously as possible.

Coun David Caunt, chairman of the joint committee of the seven West Midlands District Councils, said: "We welcome Teachers and VFMC as our partners at Birmingham Airport and look forward to working with them to continue the development of the airport but in a manner which mitigates the impact of operations on the environment and local communities."