They became the biggest band in the world, but without a dilapidated building in Liverpool, a lucky bet on a race horse and one woman’s ambitious dream, the Beatles may never have existed.

The Casbah Coffee Club, owned by the mother of the band’s original drummer, Pete Best, is where it all began for the Fab Four. She purchased the building after winning a bet and gave the Quarrymen – the precursor band to the Beatles – a residency.

And now, what was once also the Best family home in West Derby has been turned into holiday flats – available to rent on Airbnb by Beatles fans the world over.

“The first time I ever saw this building, my mother, Mona, brought me round to see it and it looked like Dracula’s castle to be quite honest,” Pete Best, 82, said.

“It was overgrown, it had been an old Conservative Club, which had lain empty for years, but Mona fell in love with it, and she wanted it.”

Unbeknown to her family, Mona Best had pawned all her jewellery and put the money on a bet – that Never Say Die, a 33-1 outsider, ridden by the then-novice jockey Lester Piggott, would win the 1954 Epsom Derby.

Pete Best recalls watching the race with his family, “and as the horse was winning and coming past the finishing post, she suddenly jumped up and started screaming: ‘I’ve won the house, I’ve won the house, I’ve won the house!’” He said: “It was only then that she told us what she’d done.”

Not only did Mona Best succeed in bringing the property back to life, but she is also credited with changing the course of musical history when she decided to open a music venue in the cellar – the Casbah Coffee Club – in 1959.

She booked a resident band – the Les Stewart Quartet – with George Harrison among the members. But they split up before they had a chance to play there.

“George basically turned round and said: ‘I happen to know a couple of guys who aren’t doing anything,’” Pete Best said. “They turned out to be John Lennon and Paul McCartney.”

The band became the Quarrymen, who played the venue 13 times – for a fee of £3 between them – and when they later returned from Germany as the Beatles, they performed there more than 40 times.

The building is one of the most important in British musical history, and now Beatles fans from around the world have the chance to spend the night in the building where their idols began.

With rooms starting from £150 a night, bookings have already come in from Canada, the US and Scotland, as well as England.

The Casbah closed in 1962, but later reopened as a tourist attraction. The Best family also run a Beatles museum in the city centre.

“At the museum, we’ve had every nationality under the sun,” Pete Best said.

The idea to open the rooms came from Pete’s younger brother, Roag, 62, son of Mona Best and the Beatles’ road manager Neil Aspinall. He was born in the room that is now known as the McCartney suite, and has worked six days a week for three-and-a-half years to bring his vision to life.

“I became not just the supervisor on site, but part of the workforce,” Roag Best said. “I’ve gone from plaster in my eyes, to a nail through my foot, to a scaffold bar hitting me on head – so I’m a fully fledged builder now.

“I was born in the McCartney suite and presented to John, Paul and George, who were here that night, they’d played the Cavern. So some of the first people I ever saw in the world were the Beatles.”

There are also rooms named after Lennon, McCartney, and the Beatles’ original bass guitarist, Stuart Sutcliffe, who left the band to stay on in Hamburg to pursue a career as a painter – as well as Pete Best.

The rooms are decorated with a light dusting of Beatles memorabilia, with photographs, posters and guitars on the wall.

However, there is no suite named after Ringo Starr, who replaced Pete Best as the band’s drummer. However, he says, there is no bad blood.

“I still don’t know the reason today, but it doesn’t worry me one iota,” he said. “As far as I’m concerned, it happened 60-odd years ago, and I’ve lived my life, I’ve had a great life.

“It did cause me initial heartache and resentment, but that’s showbusiness.”

Roag best added: “Everything we do is about being authentic and the Beatles that performed and partied here were John, Paul, George, Pete and Stuart. Ringo was never a member when he was here.”

Some of the first guests to stay in the renovated rooms, which occupy the upstairs floors of the building, were Evelyn Weatherston, 62, a psychiatric nurse, and her partner Andy Rees, 62, a decorator, from Glasgow.

“We’re big Beatles fans,” said Weatherston. “We’ve been to the Casbah before, and the history of the Casbah, it’s very special … the fact that you can now stay here is very exciting, so we were keen to come as soon as we could.”

For the Best family, the renovation has been a labour of love, and they are delighted to see Mona’s legacy live on.

“I think she’d be delighted,” Pete Best said. “She had a dream … she brought music to the kids of Merseyside.

“I think if she’d still been here today – and she’s watching from above, I’ll tell you that now – she’d be very proud, of the legacy that’s been left, and the legacy that we’re building.”

Roag Best added: “My mum would be absolutely over the moon with how this property looks now. So it’s nice to make her proud, you always want to make your mum proud.”