Work on the 2800 tonne wave-shaped roof is considered one of the most complex engineering and construction challenges of the Olympic Park ‘big build’.

The 17,500 seat Aquatics Centre will mark the 'gateway' to the Olympic Park during the 2012 Games and will host swimming, diving and water polo. After the Games it will provide elite and community facilities including two 50m swimming pools and a diving pool.

A 70-tonne steel truss has been put in place on top of the southern wall and more will be assembled in coming months.

Main contractor Balfour Beatty is overseeing the work. The steelwork has been fabricated by Rowecord Engineering.

ODA chief executive David Higgins said: “The Aquatics Centre is on track to be a fantastic gateway to the Games and provide swimming and diving facilities in legacy that London does not currently have.

“The lift of the sweeping wave-shaped roof is one of the toughest construction and engineering challenges on the Olympic Park and will showcase the world class expertise involved in delivering the venues and infrastructure for London 2012."

Once the steel roof is in place this summer work will begin on the aluminium roof covering. Installation will then start next year on the timber cladding of the ceiling which will sweep outside to cover the northern roof supports.

Work will begin on the pool structure once the steel roof is complete.