Sam Allardyce has left his post as England manager by mutual agreement with the Football Association after one match and 67 days in charge.
It follows a newspaper investigation claiming he offered advice on how to “get around” rules on player transfers.
Allardyce, 61, is also alleged to have used his role to negotiate a deal worth £400,000 to represent a Far East firm.
An FA statement said Allardyce’s conduct ‘was inappropriate’ and Gareth Southgate will take temporary charge.
“He accepts he made a significant error of judgement and has apologised,” the FA said.
“This is not a decision that was taken lightly but the FA’s priority is to protect the wider interests of the game and maintain the highest standards of conduct in football.
“The manager of the England men’s senior team is a position which must demonstrate strong leadership and show respect for the integrity of the game at all times.”
Allardyce succeeded Roy Hodgson in July following England’s disastrous performance at Euro 2016 in France and becomes the national side’s shortest-serving full-time manager.
The Daily Telegraph said Allardyce had a meeting with undercover reporters posing as businessmen before he took charge of his first England training session.
During the meeting, which was recorded on camera, it is alleged Allardyce said it was ‘not a problem’ to bypass rules on third-party player ownership and claimed he knew of agents who were ‘doing it all the time’.
It was further alleged that a £400,000 deal was struck for him to represent the company to Far East investors and to be a keynote speaker at events. Allardyce met FA chairman Greg Clarke and chief executive Martin Glenn on Tuesday to offer what he called a ‘sincere and wholehearted apology for my actions’.
He explained it had been ‘a great honour’ to be appointed England manager in July and that he was ‘deeply disappointed at this outcome’.
“Although it was made clear during the recorded conversations that any proposed arrangements would need the FA’s full approval, I recognise I made some comments which have caused embarrassment,” he added.
“As part of the meeting, I was asked to clarify what I said and the context in which the conversations took place. I have co-operated fully in this regard.
“I also regret my comments with regard to other individuals.”
Clarke told the BBC he had not been sacked, but they had agreed his position was ‘untenable’.
In an interview on the FA website, Glenn said Allardyce was ‘distraught’ but that ‘discussing a range of issues from potential contraventions of FA rules through to personal comments frankly just don’t work when you’re the manager of England’.
However, Glenn did add that it was a “really painful decision” as the FA believed Allardyce was “a great fit for England manager and we think could have been extremely successful”.
Former Blackpool, Notts County, Bolton, Newcastle, Blackburn, West Ham and Sunderland boss Allardyce won his only game in charge of the national team last month.
An injury-time goal from Liverpool’s Adam Lallana gave England a 1-0 win over Slovakia in the first of their 2018 World Cup qualifiers.
Allardyce was due to announce his squad for the next round of qualifiers on Sunday but now Southgate will be in charge for four matches against Malta at Wembley (8 October), Slovenia away (11 October), Scotland at home (11 November) and Spain in a friendly (15 November) as the FA searches for a successor.
Southgate ruled himself out of running for the England manager job prior to Allardyce’s appointment but the current bookmakers’ favourite may become a contender, depending on results in his caretaker spell.
Bournemouth’s Eddie Howe, Crystal Palace manager Alan Pardew and former Hull City boss Steve Bruce are also among the possible candidates.
What is ‘third party’ ownership?
Third-party ownership occurs when investment companies take a stake in the economic rights of players.
It was described as a form of “slavery” by Michel Platini, the former president of European football’s governing body Uefa.
The practice was banned by the FA in 2008 and by Fifa in May last year.