PRIME Minister David Cameron and First Minister Alex Salmond led the tributes to Sir Alex Ferguson after he announced he would stand down as Manchester United manager at the end of the season.

The 71-year-old Glaswegian ends a 26-year tenure at the club during which he won 49 major trophies, including 13 Premier League and two Champions League titles.

While former players hailed his extraordinary record of winning trophies at United, Mr Salmond said Ferguson's trophy haul in Scotland, at his previous club Aberdeen – rather than the success he had at United – proved he was an all-time great.

While at Aberdeen between 1978 and 1986, Ferguson broke the dominance of Glasgow giants Celtic and Rangers, who between them have monopolised the title of Scottish champions since. He even managed to lift the European Cup Winners Cup with Aberdeen, beating European giants Real Madrid in the 1983 final and defeating Bayern Munich on the way.

"He's had a fantastic career," Mr Salmond said. "I'm pleased he's managed to catch everyone by surprise because I know he'll be pleased.

"I still think the greatest test of a real football manager is the ability to win the biggest prizes with unfashionable sides or less powerful teams.

"I still think that winning the European Cup Winners' Cup is the indication that what we're talking about here is one of the all-time great football managers."

Mr Cameron, a supporter of Premier League strugglers Aston Villa, tweeted: "Sir Alex Ferguson's achievement at MUFC has been exceptional. Hopefully his retirement will make life a little easier for my team."

Labour leader Ed Miliband tweeted that Ferguson was a "Proud man. Great manager. Staunch Labour Party supporter."