When Michael Applin walked through the doors of the TopGolf driving range in Chigwell to practice his swing, he little suspected that he was about to become their one millionth customer.

But staff had been counting and when the IT worker, of Hill Road in Theydon Bois, turned up he was told he was to be given a one-off chance to win a million pounds – if he could sink a hole-in-one.

He said: “I was really surprised when they told me I was their millionth visitor, but I was absolutely stunned when they said I was getting the chance to shoot for £1 million.

“I’ve played since I was about 12 but there have been some huge gaps in between. I’ve only played twice in the past two years so it’s been a while.”

Details of how long the hole is and where the attempt will take place remain shrouded in secrecy because of tense negotiations between the centre and nervous insurers who will have to pay up if he holes out.

But Mr Applin, 39, who plays off a handicap of 24, has been practicing hard since being told of his shot at the big time, and son Rory, ten, and daughter Erin, six, already know what they want if their dad manages to pull off the big one.

He said: “The kids are very excited. They want a trip to Florida, a Wii and a puppy.”

While many golf professionals play an entire career without hitting-a-hole in one, every club in the land boasts an amateur member who has achieved one, and Mr Applin himself once thought he had when his ball rolled across a hole from 125 yards at Royal Lytham and St Annes.

He said: “I was with quite a lot of fellows at the time and to have bought champagne for all of them would have been very expensive.”

He will certainly have a lot of drinks to buy if he scores an ace this time.

He said: “It’s about having one sweet shot really. It’s a big ask but it’s an opportunity.”