Investigators from Her Majesty's Revenue and Customs (HMRC) have interviewed finance directors at Britain's richest clubs to find out about soccer players' benefits, according to The Mail on Sunday.
HMRC refused to confirm the investigation but it was reported they have been asking for details of free holidays, luxury accommodation and other gifts.
The information will be checked against players' tax returns to see whether players could be liable for any unpaid tax or if clubs may have to make additional National Insurance contributions, the newspaper added.
It quoted a source as saying: "We are not talking about a few low-cost gifts. These people are multi-millionaires.
"We wouldn't be doing this if we didn't think it was going to bring in a lot of money.
"It doesn't matter where you come from. If you work in the UK you are liable to pay tax on your UK earnings."
A spokesman for HMRC said: "We cannot discuss individual cases under any circumstances.
"For benefits in kind, the basic rule is that if an employer provides an employee with anything other than pay, it may count as an expense or benefit, and they will need to check whether they need to report it to HMRC and pay any tax or National Insurance contributions.
"Common examples of expenses and benefits include company cars, health insurance, travel and entertainment expenses, and childcare."
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