The crane from London rescued the toppled crusher

The demolition crusher, which is the height of a three storey building, collapsed in Old Town Street.

Several demolition workers had a narrow escape when the machine fell on the former site of the city's Mothercare store on Tuesday.

It is thought the base of the machine broke through into an undetected void below ground. No one was hurt.

Damage inspection

After the machine collapsed, several failed attempts were made on Tuesday evening to lift the crusher upright using a larger rescue crane.

But another crane from London was successful in righting the toppled crusher on Wednesday afternoon.

People who gathered to watch speculated about the cause of the accident.

Peter Hitchcock, who watched the crusher being rescued, said: "We often wonder what might be under there.

The crusher was believed to have fallen through a cavity

"All this was flattened during the war. After the reconstruction, it does raise the question as to how many other, shall we say cellars, were covered over and records of them lost."

Duncan Rudall of Newton Abbot company Gilpin Demolition, which owns the 330 CAT crusher but had rented to the company carrying out the work, said: "This is one of the only such machines of its type in the country, worth about �250,000.

"We don't know how badly damaged it is yet. We've got to lift it up, lower it to the ground and then we can investigate any damage to it."

The Health and Safety Executive is looking into the cause of the accident.

Demolition work started last month as part of the �170m revamp of Drake Circus.

It is hoped the new shopping centre, a 60,000 square metre development featuring 45 shops, cafes and restaurants, will be ready to open in autumn 2006.

The Mothercare store, which has relocated to another part of the city centre, was the first of several stores to be demolished.