The ATP says prize money has increased by $70m (£54m) in the past five years, and can point to the $28.5m (£22m) of prize money available to emerging and lower ranked players on the Challenger Tour this year.

A profit-sharing model was introduced in 2022 and ensures players receive 50% of the profits generated by the ATP’s nine Masters 1,000 tournaments.

The ATP’s prize money formula sets a minimum level for different categories of tournaments. For a Masters 1,000 event with a 96-man draw, for example, that figure is $9.193m (£7.1m).

There is, in theory, no maximum, although if an owner wants to raise prize money by, say, 50% they would need to do so evenly across the draw.

The WTA says $221m (£170.5m) of prize money was distributed last year – $42m (£32m) more than in 2023.

The ITIA’s out-of-competition drug tests take place between 5am and 11pm. Players have to provide a one-hour time window when they will be available for every day of the year.

They must also hand over their mobile phones to investigators, as this is often a vital source of evidence when there is suspicion of corruption.

All requests to investigate a player’s phone must first be signed off by the ITIA’s investigations director.