Building the London Olympic Stadium's new roof

The BBC has been allowed inside London's Olympic Stadium to film the construction of the arena's new roof.

The new structure is one of the largest of its kind and unlike its predecessor will cover all spectators within the stadium.

It forms part of a £190 million transformation programme which also involves the installation of new hospitality suites, toilets and turnstile areas.

Costs have risen by £36 million because of the need to strengthen existing steelwork.

The stadium is scheduled to reopen next year to host 2015 Rugby World Cup games. Football club West Ham United are set to move to the arena in 2016.

Project director Stuart Fraser told BBC News about the work which is being done.

Video journalist: Neil Bowdler