Wall collapse in Mount Hermon is third in 20 years in the area

But the crashing down of the granite blocks, tonnes of earth and part of a driveway failed to wake the owners of the house, who were sleeping just metres away.

The wall on Mount Hermon, St Peter Port, close to the top of Victoria Road, came down in the early hours of yesterday morning, completely blocking the adjacent narrow lane, Les Petites Fontaines, and knocking down the scaffold recently erected to restore it and a nearby lamppost.

The homeowner, who asked not to be named, said work had just begun to fix the wall, which had been bulging.

‘The scaffold was up and some of the stones had been removed,’ she said.

‘We had permission in place to close Les Petites Fontaines so the work could be done. I’ve no idea what happened to cause this.’

Amazingly the owners of the house were not woken when the driveway and wall collapsed – a sound other neighbours described as ‘like a bomb going off’.

‘We only knew when the fire brigade came,’ the homeowner said. ‘It has all been a bit of a shock.’

Neighbour Eugenia Nobrega said she had been woken by ‘a big bang’ just before 1am.

‘We immediately raced to look out the window and my neighbours called the fire brigade,’ she said.

‘They, the police and electricity company, were here until about 4am. They were also checking no one could smell gas. We have all had a bit of a sleepless night.’

This is not the first time a retaining wall has buckled along this stretch of Les Petites Fontaines. A section of wall close to last night’s incident collapsed in both 2007 and 2012, around the time the current properties, that sit above the wall, were being developed.

Guernsey Fire & Rescue services confirmed two fire engines attended the collapse to make sure it was structurally sound.

‘The collapsed wall affected a retaining wall and driveway of the property,’ a spokesman said.

‘It had knocked over a streetlamp and was also impinging on a neighbouring property. Our main actions were to put a cordon in place due to the electrical hazard and clear what debris we safely could.’

Guernsey Energy engineers also attended to ensure that no gas services had been affected.

A Guernsey Electricity spokesman said engineers were called out to Mount Hermon at about 1.15am and had to cut off power to some of the surrounding properties to isolate the damaged street light.

‘Upon completion of the wall repairs and once the site is made safe, engineers will return at a later date to replace and make live the street light,’ he said.