Newcastle United managing director Lee Charnley has reportedly been arrested in relation to transfer dealings.
The HMRC has raided offices at both the North-East club's home St James' Park and West Ham United's ground the London Stadium.
Several men working within the football industry have been arrested on suspicion of income tax and national insurance fraud.
A statement read: "180 HMRC officers have been deployed across the UK and France today. Investigators have searched a number of premises in the North-East and South-East of England and arrested the men and also seized business records, financial records, computers and mobile phones.
"The French authorities are assisting the UK investigation, have made arrests and several locations have been searched in France."
Reports from The Independent and other media outlets have claimed that Charnley is one of the men that has been detained by police in relation to the investigation.
The news comes just two days after Newcastle secured promotion back to the Premier League with a 4-1 victory over Preston North End on home turf.
