EXCLUSIVE: Gareth Southgate's soon-to-be-former agent is suing the FA for MILLIONS over how they terminated his deal to handle commercial work of England stars including Harry Kane

Gareth Southgate's agent is suing the FA for millions of pounds over a long-running dispute involving the commercial deals of senior England stars. 

Mail Sport revealed on Monday that Terry Byrne owes money to Southgate, Joe Cole and Glenn Hoddle after using fees received by his company 10Ten for their commercial work to help fund a £25million property deal without their permission.

In a separate development that could also cause discomfort for the England manager, Mail Sport has learned that Byrne is engaged in a legal dispute with Southgate's employers. 

Byrne is understood to be claiming that the FA breached their contract with another of his companies, 1966 Entertainment, by terminating a deal involving England players' commercial appearances that was due to run until 2030.

Byrne has accused the FA of 'tortious interference' in 1966 Entertainment's long-standing contract with England's players, which was originally negotiated by then captain David Beckham on the squad's behalf in 2006 and was later extended. 

The FA first sought an early exit from the deal in 2018, but were unable to agree severance terms with Byrne and then cancelled the contract, even blocking Byrne and his staff from visiting England's players at St George's Park.

The FA are still hoping to resolve the matter without the scrutiny of a high-profile court case, but Byrne is claiming millions in compensation and is understood to be in no mood to settle. 

An initial arbitration hearing has been set for December 12, but if no agreement is reached the case will go to court.

The FA's discomfort has been compounded by the fact that Byrne has also represented Southgate since 2016, although the manager may sever ties with the agent following Mail Sport's revelations about the missing money. 

While the pair remain on good terms Southgate is seeking to be repaid a significant sum and FA sources expect Southgate to use a different agent next year when his contract is up for renegotiation.

The FA's decision to sever ties with Byrne and 1966 was taken following Mark Bullingham's appointment as commercial chief at Wembley in 2016, a position he left three years later to become chief executive. 

The FA served notice to 1966 before the 2018 World Cup and the row has rumbled on ever since.

The FA and Byrne declined to comment.