Rats are being blamed for contributing to caverns under main roads in Gorleston after a second sinkhole opened up yesterday.

There was further frustration yesterday after a hole opened in High Road, near the junction with Burnt Lane, revealing a two metre-deep cavity only five days after a hole opened in the nearby High Street.

A lane was closed for 'safety reasons' while investigations began into what caused not one, but two cavities under the adjoining roads.

Norfolk County Council is no closer to determining exactely what caused the voids, but yesterday said workers found evidence of rat runs under the High Street hole.

A spokesman said it was possible the rats, moving through loose sandy subsoil, may have contributed to the collapse. Recent wet weather could also be a contributing factor.

Voicing concern Great Yarmouth borough councillor Marie Field said: 'Maybe now someone will listen and not turn a blind eye to the extent of our highly rat populated sewers.

'The water companies need to go back to chemical implementation down our sewers twice yearly. Saying that, it maybe too late to stop the damage that they have already caused down under our road systems.'

Today, council workers will continue to excavate the High Street. Anglian Water and Virgin Media have been called back in to check sewers and ducts.

A council spokesman said the appearance of a second hole had been 'frustrating' and investigations 'difficult and slow' because of the number of utility services including a sewer with side connections, water and gas mains and electricity cables.

'With about two-thirds of the excavation complete, no obvious cause of the subsidence has been found,' he said.

'All the utility pipes and cables appeared in good condition.'

If no leaks are found, the council said it hopes to fill the High Street hole by Friday.

The normally busy road has been closed to traffic since Friday when the hole opened outside the QD Stores. Shops remains open and a traffic diversion is in place.