Jose Mourinho's contract negotiations to become the next manager of Manchester United appear to hinge on the rights to the use of his image on merchandise, British media reported on Thursday.

The rights are owned by his former club Chelsea and, while they are not expected to stop his hiring, they have drawn out the talks with Manchester United this week, the reports cited club sources as saying.

Mourinho was the manager at Chelsea before his sacking in December and the shop at the Blues' Stamford Bridge ground still sells mugs, posters and phone cases bearing his image.

The Guardian newspaper reported that the west London club bought the image rights in 2005 during his first stint as manager, and wants to sell them at a high price.

Chelsea registered the brand "Jose Mourinho" for five types of merchandise until 2025 and for the others until 2023 under European Union intellectual property laws, the report said.

Chelsea have not commented on the information but the rights issue was no impediment to Mourinho going on to work at Inter Milan and Real Madrid before coming back to Stamford Bridge.

Sports lawyer Carol Couse told the BBC it was "really unusual" for an individual not to own the trademark to their own name.

"If United had a brand of Mourinho clothing, it would be in breach of the trademark Chelsea currently own," said Couse, of law firm Mills and Reeve.

"If Chelsea didn't grant a licence, every time United used Jose Mourinho's name in a commercial capacity against those products, Chelsea could sue Manchester United," she said.

"I would suspect United would rather just pay a licence fee."