I worked out with a £1,000-per-hour personal trainer - his clients include Olympians, CEOs, and celebrities

On the way to an appointment with one of London's most expensive personal trainers at his private studio in Kensington, I started to feel anxious.

What will Fabrice Le Physique do to my body to justify his top rate of £1,000 per hour? I imagine futuristic machines that will pull and twist my weak limbs in all directions, while a toned trainer screams expletives until I finally break.

The exact location of the gym is given out on a strictly need-to-know basis. Part of Fabrice's appeal to clients is his tight-lipped discretion. He says this has allowed him to attract a client list of presidents, Hollywood A-listers, billionaires, and even British athletes competing at this summer's Olympics in Rio. Actor Matt Le Blanc and billionaire mineral magnate Patrice Motsepe are two customers who have foregone this privacy and offered public endorsements to Fabrice on his website.

There are more than 20,000 personal trainers generating £626 million in revenue per year in the UK, but Fabrice is part of a more select group of elite trainers.

When I arrive at the stucco-fronted terraced house, a short walk away from High Street Kensington, I calm down. The two-floor studio inside contains pristine but standard gym equipment, a large flat screen TV, and the reassuring thud of chart music that you would find in your local branch of Fitness First.