Sir Alex Ferguson is back on board at Manchester United after the club's chief executive Richard Arnold turned to the legendary Old Trafford boss for advice.

Arnold has set up a think-tank involving Ferguson, former CEO David Gill, iconic United captain Bryan Robson and current football director John Murtough so he can draw on their experience on all aspects of the club. It will give Ferguson more influence at Old Trafford than at any time since he stepped down as manager nearly a decade ago.

Tuesday's lunch meeting at Carrington – which coincided with Cristiano Ronaldo's return to the training ground for talks – is understood to be the first in a series of regular meetings involving the five men.

Although Ferguson and Gill have remained on United's football board as non-executive directors since leaving their jobs in 2013, it has been seen as a largely symbolic gesture with former United chief executive Ed Woodward choosing to do things his way.

Sportsmail revealed in November that Ferguson would welcome the opportunity to have more input at United after only being consulted on a handful of occasions by then manager Ole Gunnar Solskjaer. Now 80 years old, and having recovered from a life-threatening brain haemorrhage in 2018, the Scot can no longer play an active role at United.

But Arnold, who succeeded Woodward in February, has recognised the importance of tapping into Ferguson's vast football knowledge having lifted an unprecedented 38 trophies during his 26-and-a-half years in charge at Old Trafford.

Gill played a key part in that success during his 16-year spell at United, including a decade as chief executive, but he too has been a peripheral figure at the club in recent years despite his standing in the game. Gill, 64, sits on UEFA's executive committee and is also treasurer of European football's governing body, as well as chairman of both the finance committee and compensation committee.

Robson is revered as a United legend and also works as an ambassador for the club, like Ferguson. It's understood the three men will advise Arnold on a wide range of issues which include the redevelopment of Old Trafford and Carrington, and the club's relationship with its fans.

It will inevitably involve football matters as well, although they will be careful not to tread on Murtough's toes. Ferguson spoke to Ronaldo when the player and his agent held talks with Arnold on Tuesday, but it is understood to have been a brief chat when the player approached his old manager. Club sources insist their encounter was a coincidence because Ferguson's lunch meeting had been in the diary for some time. However, it's understood that the venue may have been switched to Carrington so Arnold could meet with Ronaldo and Mendes.

And having Ferguson – who persuaded Ronaldo to stay for an extra year at United in 2008 – in the building would have been another smart move by Arnold. It's fair to say that he has seen the error of Woodward's ways if his first six months in the job are anything to go by.