THE collapse of a house in Penarth was caused by renovation work to build an underground extension, it was been revealed.

Work at the Clinton Road property were meant to add extra rooms to the four-bedroom property but the rear walls crumbled and the rear of the house collapsed into the planned new basement.

After the incident on Friday, June 10 sniffer dogs and rescue teams were sent to the house to check if anyone was trapped inside and safety chiefs shut down gas and electric supplies.

The house's owner, cosmetic surgeon Sid Gautam, 36, said the work was to make the house a six-bedroom family home in the same 1920s style and the basement is for extra storage and a playroom for children.

He said: "It's frustrating, unforeseen and irritating to lose this time on the project.

"The delay is not through lack of will or funds. We bought the house a couple of years ago. Work started more recently and due to issues with our contractor we have faced delay after delay.

"Luckily it’s a house of two halves. The front is strong, but the insides have fallen in.

"Ultimately it's a groundwork issue and we're in the process of getting new guys in because the contractors haven't delivered."

Fire station manager Justin Jones said: "This shouldn't have been allowed to happen. The site is still very dangerous and will be boarded up.

"We were alerted by the collapse by a workman who had come to collect some tools.

"He is believed to have been the only person on site but we have sniffer dogs at the scene to confirm this.

"Safety boarding to put up and the existing contractor has been sent off site."

The house's former owner, winemaker Ian Symonds, said the property was sold to Mr Gautam in October 2014 in excess of £800,000.

Mr Symonds said: "I lived there for 33 years and have many happy memories of our time in that house. It's very sad what's happened to it."

A spokeswoman for South Wales Fire and Rescue said: "We were called Clinton Road, Penarth at 10.43am to a house under renovation. The rear of the property had collapsed.

"No persons were trapped and the local authority health and safety executive are in attendance to locate gas and electric supplies to isolate them."

A spokesman for South Wales Police said: "We attended to make sure the area was safe but were later stood down."