The Glazer family are struggling to refinance the massive debts at Manchester United, it has been revealed.

The Times says the Americans have been trying unsuccessfully to secure a refinancing package for part of the club's £699 million debt for months, having failed in 2007 and last year, because of the bleak global economic climate.

Fans' groups have cast doubt over whether they will ever see the £80 million raised from the sale of Cristiano Ronaldo, the Portugal forward, to Real Madrid last summer reinvested in the squad.

The main concern is understood to centre around the £175.5 million worth of debt that the Glazers are personally responsible for, not the £518.7 million of loans secured against the club.

A spokesman for the Glazer family said: "We continue to keep our financial options for the club under review just like any other business."