Louis van Gaal arrived at Manchester United's training ground at 0845 BST on Monday with the club still expected to replace him with Jose Mourinho.
Forty-five minutes later, League Managers Association lawyer Paul Gilroy QC also drove into Carrington.
Gilroy is the same employment barrister who acted for David Moyes when he was sacked as manager by United in 2014.
The BBC understands that Saturday's FA Cup final win over Crystal Palace was Van Gaal's last game in charge.
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Van Gaal, 64, was alone as he drove into Carrington on Monday.
Gilroy arrived around 0930 and was initially refused entry.
He returned approximately 15 minutes later and was allowed in, refusing to answer questions about the reason for his presence.
According to his profile page on the Nine St John Street Chambers website, Gilroy has advised and acted for a number of football clients.
They include Roy Hodgson, Martin O'Neill, Sir Alex Ferguson, Harry Redknapp, Roy Keane, Roberto Martinez, Sam Allardyce, Brendan Rodgers, Alan Pardew, Nigel Pearson and Steve McClaren.
Chambers and Partners, which ranks the best lawyers, describe Gilroy as "a noted employment specialist" who is "renowned for getting a fantastic deal for managers".
Before he left London after United's FA Cup success, Van Gaal told some staff that he did not know if he would see them again, although he said later that he still "hoped" to be in charge for the final year of his three-year contract.
The Dutchman said "it's over" when a reporter approached him as he departed the team hotel on Sunday.
However, the former Netherlands, Barcelona and Bayern Munich manager is said to have been referring to his side's season rather than his own job.
BBC Sports editor Dan Roan:
"In April 2014, United's mishandling of the sacking of Moyes was heavily criticised, the coach humiliated when learning of his demise through the media.
"The club's hierachy accepted it was wrong that news had leaked out before the manager had been informed. But two years on, it has happened again.
"Van Gaal was apparently informed of his impending departure by his wife when - still at Wembley following the club's FA Cup Final win - she read the news on the BBC website on Saturday evening.
"United hold the Dutchman in high regard and had desperately tried to maintain secrecy during their negotiations with Mourinho, hoping Van Gaal would lead his team to a top-four spot in the Premier League.
"Even after that target was missed, the club wanted him to be able to enjoy his FA Cup win, never once briefing against their coach or adding to the speculation. But it was always naive to think that news of their plans would remain secret.
"Once the news broke on Saturday, it was hard to fathom why they waited to put Van Gaal out of his misery. Once again serious questions will be asked about the way the Glazer regime runs the club - and the way it communicates."
Another new manager
Mourinho would be the third boss at Old Trafford since Sir Alex Ferguson stood down at the end of the 2013 season after 26 years in charge.
Moyes lasted 10 months before being replaced by Van Gaal, who took over in July 2014 after guiding the Netherlands to third place at the World Cup.
Mourinho is due to hold talks with senior United officials on Tuesday.
Some members of Van Gaal's Old Trafford staff are believed to be unhappy at the lack of communication from the club's hierarchy.
United's executive vice-chairman, Ed Woodward, and Joel and Avie Glazer, part of the American family who own the club, were at Wembley on Saturday,
But they are not thought to have spoken to Van Gaal at a function following the 2-1 win over Crystal Palace.
As the reports about Van Gaal's impending departure spread, the function is said to have become a sombre affair.
Neither Van Gaal nor Woodward addressed staff collectively in the wake of the club's first triumph since Sir Alex Ferguson's retirement in 2013.
In the past, Ferguson or former chief executive David Gill would have expressed their gratitude for the hard work involved in winning a major prize.
BBC Sport revealed on Saturday that United are set to appoint Mourinho, who won three league titles in two spells at Chelsea,
Mourinho, 53, was sacked by Chelsea in December, seven months after the club won the Premier League title, and has been out of work since.
The former Real Madrid, Inter Milan and Porto boss was at heavyweight boxer David Haye's win in London on Saturday but repeatedly declined to comment about his future.
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