Sheikh Jassim bin Hamad Al-Thani has made an improved bid to buy Manchester United, sources have told ESPN.

Amid speculation that current owners the Glazer Family are favouring an offer made by British billionaire Sir Jim Ratcliffe, Sheikh Jassim has returned with another bid more than two weeks after Raine Group, the merchant bank handling the process, asked for final proposals to be submitted.

An offer made by Ratcliffe, chairman of chemical company INEOS, in the third round of bidding placed a higher value on United than the previous bid from Sheikh Jassim and also included plans for siblings Joel and Avram Glazer to remain as shareholders.

Sources told ESPN it had made Ratcliffe the favourite to complete a takeover before Sheikh Jassim upped his offer.