Boris Johnson has been challenged over safety for construction workers on London’s �15 billion Crossrail project.

The London Mayor was pushed for an agreement with trade unions to improve work practices following a cable explosion at a construction site when a worker received severe burns.

The challenge came at Mayor’s Question Time earlier this week by London Assembly Member John Biggs, who called for the Olympics safety measures to be applied to Crossrail.

Biggs, whose east London constituency includes the Olympic Park, said later: “One characteristic of London 2012 construction was the collective agreement on safety. Boris has made no such agreement for Crossrail which is a grave omission.”

There was no safety agreement with the unions for Crossrail which is under construction for the next five years, he pointed out.

The mayor promised to “look at ways of improving Crossrail’s safety.”

A construction worker carrying out utility excavation work at High Holborn on December 12 struck an underground electrical cable causing an explosion, said Crossrail. The Health & Safety Executive is investigating the incident.