When you leave your house in the morning, the last thing you expect is to fall down a large crater which has mysteriously appeared in your driveway.

But this is what happened to Dawn Hides as she left her home at Seavale Road in Clevedon on Monday morning.

Mrs Hides, aged 46, was walking along the driveway of the family home when she tripped and fell on a small hole in the block paving.

But minutes later the ground gave way and the driveway crumbled, leaving a terrified Mrs Hides, who was on her way to Weston College with 17-year-old daughter Alice, up to her neck in the gaping crater.

Mrs Hides, who runs her business So To Sew from home, said: "As I came out of the front door and stepped down onto the driveway I noticed two of the paving bricks had gone, but didn't really think anything of it.

"Then before I knew it I was in a hole up to my shoulders and I couldn't get out, as every time I tried to grab hold of something, more of the driveway kept sliding away."

Over the next hour, more and more of the driveway collapsed, eventually leaving a 20ft crater.

Mrs Hides's husband Nick, aged 46, had taken the week off to work on the house and said the couple were woken that morning by a strange, rumbling noise.

Mr Hides, an engineer for Hewlett Packard, said: "At about 7.45am we woke to a rumble and thought it was thunder.

"Then, just after Dawn left the house, I heard her shouting my name and saw the hole.

"Luckily Dawn was okay and somehow we managed to get the car off the driveway without that being lost down the hole."

When contractors came to fix the hole, they brought two bags of sand, thinking Mrs Hides who suffered scrapes and bruises in the incident, and her husband may have been exaggerating slightly.

Vincent Weaver, of Olympus Construction, said: "We come across a lot but have never seen anything like this."

The family now face spending Christmas with family, friends or in a hotel, while work to repair their home is carried out.

The hole has revealed a bricked archway about 10ft down and the couple, who have lived in Seavale Road for 12 years, would now like to find out as much information about their house as possible.

Mrs Hides says she believes it was once the tax collecting office for the Elton estate, and dates back to 1776.

The family has been left wondering if the archway could be part of a former cellar or was an old water storage tank.

Local historians Jane Lilly and her uncle Derek Lilly said they could not find any reference to there being a tax office in the area.

Ms Lilly said: “I haven't come across any reference previously at Clevedon Court to a tax office at all.

"I think the Seavale Road houses date to the early 1860s, just after the mains water was being laid on in 1856, but if the tank or hole is arched that would be to support its cover at ground level.

"It could be a water storage tank for rainwater, directed off the roof guttering to be used for laundry."

Clevedon Civic Society president Julia Elton, who is an expert in civil engineering history, agreed with Jane Lilly's comments.

She said: "This is very interesting.

“I would have thought a tax collecting office for the estate would have more likely been in lower Clevedon and the arch could be part of the sewers of a water tank store.

"Arthur Hallam Elton, who is mentioned in the house deeds, was the 7th baronet and it was he who built the gas works, water works and the hospital."