Call to ban tunnelling technique

Labour called for a ban yesterday on the tunnelling technique used at Heathrow where a series of collapses at the weekend brought chaos to the airport, writes Danny Penman.

Michael Meacher, shadow Transport Secretary, said the method should not be used until it 'could be proved safe'.

The new Austrian tunnelling method - originally developed for excavating rock - was being used for the first time in London clay at Heathrow.

Developed in the 1960s, it was used on sections of the Channel tunnel but engineers are concerned that it may be inappropriate for London clay.

Doubts were first raised after the collapse of a tunnel in Munich earlier this year, which opened a crater in a main road, swallowing a bus and killing two people.

Mr Meacher, in a letter to Brian Mawhinney, the Transport Secretary, sought an assurance that no further tunnelling using the Austrian method will be allowed until a report is ready on the Heathrow collapse.

The method involves sinking a vertical shaft and then excavating with earthmovers. As the cavern is opened the walls are lined with steel netting and sprayed with concrete.