Jose Mourinho could miss vital Manchester United training sessions this week as he fights accusations of tax fraud in Spain.

United boss Mourinho is due to return to former club Chelsea on Sunday, where the Portuguese won the Premier League title three times.

But his preparations could be disrupted as he is due to face charges dating back to his time as Real Madrid chief.

Mourinho is alleged to owe Spanish authorities almost £2.9m in undeclared revenue related to image rights in 2011 and 2012, as originally reported in the Manchester Evening News.

Mourinho is alleged to owe Spanish officials £2.9m (
Image:
Action Images via Reuters)
Mourinho won La Liga, Copa del Rey and the Spanish Super Cup at Real (
Image:
AFP/Getty)

That has been strenuously denied by his representatives but the Reds boss has been summoned to appear in a Madrid court on November 3 - two days before he takes United back to his former home at Stamford Bridge in the Premier League.

It is understood United's first-team players have been made aware of an altered training schedule.

The allegations against Mourinho are part of a wider drive by the Spain authorities against tax fraud, with several leading figures in football having been investigated.

Mourinho could miss United training to travel to the hearing (
Image:
AFP)

His representatives, Gestifute Media, said: "Jose Mourinho, who lived in Spain from June 2010 until May 2013, paid more than 26 million euros in taxes, with an average tax rate over 41 per cent, and accepted the regularisation proposals made by the Spanish tax authorities in 2015 regarding the years of 2011 and 2012 and entered into a settlement agreement regarding 2013.

"The Spanish government in turn, through the tax department, issued a certificate in which it attested that he had regularised his position and was in compliance with all his tax obligations."