HEATHROW EXPRESS tunnellers were evacuated across a stretch of ground just minutes before the tunnel collapsed, a court was told last week.
The revelation came on the first day of the Health & Safety Executive's prosecution of Heathrow Express main contractor Balfour Beatty and Austrian tunnelling consultant Geoconsult for alleged breaches of health and safety legislation.
After a short hearing on Monday, the case was referred to Crown Court, where maximum fines are unlimited. It will be heard in Isleworth on 22 June.
The HSE alleges that poor design and bad construction led to the 1994 collapse in the heart of Heathrow Airport (NCE 27 October 1994). It accuses the two companies of exposing the public to great risk and believes that it was only 'very good luck' which prevented a more serious incident.
Prosecuting counsel Keith Morton described how workers had initially been led from the failing tunnels to an area also affected by the collapse and then exposed to further danger when re-evacuated across a surface which gave way moments later.
Morton claimed it was luck that the series of progressive tunnel collapses - which started early in the morning on 21 October 1994 - began when no- one was working above ground and when Tube trains were not running.
He also argued that while remedial work had prevented the collapse of tunnels under Terminal 4, the risk in that area was also great. Cracks, he said, had appeared at those tunnels and the potential damage there was even greater than in the central area because as well as the London Underground railway line there was a road and car park running over the tunnel.
HSE alleges that 'both companies failed to ensure, so far as was reasonably practicable, the safety of their employees and others not in their employment throughout the construction of a number of tunnels by the New Austrian Tunnelling Method during May to October 1994.'
Prosecution follows a detailed investigation into the design and construction of the Heathrow Express tunnels following the collapses.
Morton described these tunnels as badly constructed and said that the unpredictability of the situation had put the public at risk. Had a tunnel under London Underground's Piccadilly Line collapsed, he added, there could have been enormous damage and derailment.
Defence lawyers said the prosecution had exaggerated its claims but also asked that the case be referred to a higher court due to its complexity.