Thousands of soldiers - some recently returned from Afghanistan - are to be called in to help with security for the Olympic Games.

That's because of fears that the private security company responsible has not trained enough staff.

The British government has admitted that 3,500 troops will be needed to cover a massive shortfall.

And with the opening ceremony just weeks away, continuing problems with London's road network are adding to concerns about the games.

Al Jazeera's Paul Brennan reports.