SIR Alex Ferguson remained in intensive care at Salford Royal Hospital last night after undergoing emergency surgery on Saturday following a brain haemorrhage.

The 76-year-old footballing legend appears to have survived the devastating brain attack, but medical experts say the 48 hours after the operation are crucial.

Ferguson became seriously ill at his home in Cheshire on Saturday morning and was rushed to a hospital in Macclesfield before being taken to Salford Royal for the operation which may well have saved his life.

The former manager of Manchester United, Aberdeen, St Mirren and East Stirlingshire, who has won more trophies than any other British manager, could make a full recovery but the likely prognosis will not be known for weeks, if not months.

The football world and many people beyond have come together to send good wishes to the former apprentice toolmaker from Govan, who led United to the European Cup, as he fights for health.

Fans of United’s great local rivals Manchester City paid tribute to him as their club celebrated winning the English Premiership title yesterday. During a pitch invasion at the close of their match with Huddersfield, two City fans could be seen holding a large banner saying: “Football aside get well Fergie.”

In Scotland, Glasgow City Council shared a photo of Sir Alex with pupils at Govan High School, adding: “Wishing Glasgow and former Govan High School legend Sir Alex Ferguson all our very best wishes & a speedy recovery.”

Ferguson has strong links to Glasgow Caledonian University, which called him a “role model” and “wonderful supporter” of the institution.

Current United midfielder Michael Carrick said on Twitter: “Absolutely devastated to hear about Sir Alex being unwell in hospital. All my thoughts and prayers are with him and his family. Be strong Boss.”

Current World Player of the Year Cristiano Ronaldo, who previously played for United and is now signed to Real Madrid, tweeted: “My thoughts and prayers are with you, my dear friend. Be strong, Boss!”

His former colleague David Beckham, who had a sometimes tempestuous relationship with Ferguson, said on Instagram: “Keep fighting Boss ... Sending prayers and love to Cathy and the whole family x,”

Ferguson’s former club Rangers FC tweeted: “Everyone at #RangersFC sends their best wishes to Sir Alex Ferguson following emergency surgery.”

Other Scottish clubs also sent messages to Ferguson and his family, with Celtic manager Brendan Rodgers saying: “It’s a big shock to us all, of course. He’s a colossus of the game; of the British game and the world game.

“So we hope that he makes the full recovery and all our regards are with him and his family.”

According to Luke Griggs, of the brain injury charity Headway, brain haemorrhages can sometimes happen spontaneously as a result of a ruptured aneurysm, otherwise known as a haemorrhagic stroke.

“A haemorrhage can also result from a blow to the head, often of a significant severity,” he added. “But it can sometimes occur after a seemingly minor head injury.”

Griggs added that the outlook for a patient can vary depending on many factors, including where the bleed occurred and the size of it.

He said: “Every brain injury is unique, as is every individual’s recovery.

“Many patients will survive a bleed on the brain, but recovery can take many months. In some cases, extensive rehabilitation is needed to regain function, including speech therapy and physical therapy.”

Manchester United said in a statement: “The procedure has gone very well but he needs a period of intensive care to optimise his recovery. His family request privacy in this matter.

“We will keep Sir Alex and his loved ones in our thoughts during this time, and we are united in our wish to see him make a comfortable, speedy recovery.”