One of the contractors injured in the explosion at Croydon police station is now in a critical condition.
The man had been taken to St George's Hospital following the blast in the decommissioned firing range in the basement of the Park Lane building yesterday.
He was initially described as serious but is now in a critical but stable condition according to police.
Another man who was airlifted to a special burns unit at Broomfield Hospital is still in a serious but stable condition.
The explosion happened at about 11.30am yesterday and left another three needing hospital treatment, but they have all since been discharged.