When mother-of-two Melanie Day settled down to watch TV last week she had no idea she was about to become a mother of three.

In fact, the 29-year-old didn't even know she was pregnant until she felt a huge contraction as she waited for partner Paul, 37, to arrive home from work.

"I put my hand down and felt the top of his head," she said.

"It was the most terrifying thing in my life," she said. "Most people have about seven months to get used to the idea that they are going to have a baby.

"I had a couple of seconds."

There had been no signs that she was pregnant: her periods had been regular, she had put on hardly any weight and there had been no cravings.

She had also been working hard just two days before painting a club house.

After the contractions on Friday afternoon, she managed to stagger into the bedroom, take her jogging bottoms off and get on the bed, where she discovered tiny Stephen's head had appeared completely.

Covering herself with a quilt and calming her elder daughter, Carla, 10, Melanie told her to shout for her father Paul. "She was very frightened so was I," she said.

Luckily, Paul had almost reached the house. "He came in and said: 'What's the matter with you?' I lifted the quilt and Stephen was halfway there."

Immediately, he called the ambulance.

"We didn't have any credit left on the phone, but luckily you can still make 999 calls," she explained.

"They told him what to do. He was shooting around looking for a clean towel and when the baby was born he cleared his mouth and nose and wrapped him up. "

Paramedics arrived 30 minutes later and took them both to the Great Western Hospital, where doctors decided 4lb 3oz Stephen was about six weeks premature.

He was put in an incubator and fed on a drip for a couple of days, while his mum was discharged on Saturday afternoon.

As soon as their families heard the good news they swung into action as Melanie had long since given away all her baby equipment.

"All I had was a pink rattle that I kept for sentimental reasons," she said.

Her dad John and stepmother Lynn bought a pushchair and carrycot, while her mother Sue went shopping for baby clothes and other equipment.

Meanwhile, the couple, who have been together since 1992, got to know their secretive new son.

"I took the girls off to the play room so Paul could have some time alone with Stephen, but I sneaked back for a look. It was really lovely seeing father and son together.

"I bonded with Stephen on Monday night when I was able to give him his first feed," she added.

Carla and he sister Vicky, eight, can't wait for their new brother to come home.

Now the couple, who live and work at a caravan site on the outskirts of Ashton Keynes, are looking for somewhere new to live.

"It was a shock at the time and I was very frightened, but I wouldn't change anything," said Melanie.

Tina Clarke