United have warned fans against donating to an internet-based campaign aimed at bringing Cristiano Ronaldo back to Old Trafford.

A group of Australian Reds have launched a drive to raise the funds needed to sign the 28-year-old Portuguese superstar, who is currently at Real Madrid.

In what many would see as an optimistic move, they believe the ‘BringRonaldoHome’ movement, which sees supporters deposit initial donations of £10 can hit the reported £100m buyout clause in the winger’s contract.

Since it’s launch last month the campaign claims to have had 5,019 pledges – but United have warned fans against backing the campaign.

A spokesman told the M.E.N.: “Manchester United would like to remind fans that decisions over additions to the squad will be made by the manager and the manager alone. We would not want any of our supporters to be under a false impression that anything other than this would ever be the case.”

The group, fronted by Stockport ex-pat Lee Clough, say the £10 deposits will, if the bid is successful, eventually be exchanged for a new United shirt with Ronaldo’s name and number on the back. When asked, that being the case, where the money to sign the player would actually come from Mr Clough, who is hoping to draw on the resources of the club’s 650m worldwide followers, said the group could ‘not reveal our strategy in full’.

He added that the success of the campaign was dependent upon kit manufacturers Nike and Manchester United, adding that the 'bulk of the funds raised will go to the club and CR7’s (Ronaldo's) transfer fee’.

Mr Clough also promised that if the bid failed, fans would receive their £10 deposits back in full, adding that plans to charge an admin fee had been dropped and denied claims that the ‘crowd funding’ system was a scam. He said: “We are a good group of people who have put an amazing amount of effort into this project.

“The model is based off a tried and successful business model of crowd-funding.

“We have contacted Manchester United at a senior level and reassured them that our intentions are only for the good of the club.

“This gives all fans the chance to be involved to assist the club to re-sign CR7.”

Ronaldo, who has two years remaining on his contract with Real Madrid, is said to have turned down a new offer.