The mystery Peterborough punter collected the enormous windfall in the early hours of Thursday playing the Pharaoh's Treasure game on William Hill's Vegas website.

The mother, whose identity is being kept secret by the betting firm and is known only as Sophie M, said winning the £102,718 prize was like a "weird and wonderful dream".

She clinched the payout, which has secured comfortable futures for her children, after laying just £4.50 on the complicated 20-line slot game and progressing to a big-money bonus round.

"I was in complete shock when I saw I had won the jackpot," she said. "It was the early hours of the morning and I went to bed thinking thank you, thank you, thank you.

"I hardly slept and I had to keep checking my balance the next morning because it felt like some weird and wonderful dream that I'd had."

Sophie said she had been gambling on the William Hill website for a year, but had only been playing the Pharaoh's Treasure game for two weeks before her victory.

She added that she had her power of recall – as well as a large helping of luck – to thank for securing the prize.

She said: "I've got a good memory so I found I was good at the bonus rounds. Really good at the bonus rounds, as it turned out. It's still unbelievable.

"I'm planning to invest the money for my family, especially my beautiful children. It will secure their future for them and I'm so proud to have such a loving family."

William Hill says it has now paid out three prizes totalling more than £240,000 to online gamblers during the past few weeks.

Spokeswoman Jennie Priest said: "We are delighted for Sophie. It's always nice to get a big winners, and we've had three big payouts in a month now.

"It is terrific for our customers because it shows people really can win a life-changing amount of money for a very small stake."