Manchester United have sacked manager Jose Mourinho after identifying a catalogue of his failings at the club.
The Portuguese, 55, took over in May 2016 and led United to League Cup and Europa League titles, but they are 19 points behind league leaders Liverpool.
The club have made a change after no progress with results or style despite spending nearly £400m on 11 players.
They also say the new manager will understand the philosophy of the club, including their attacking tradition.
It is understood players and staff are not happy after a disappointing and unsettling period during which young players were not developed.
United are sixth in the Premier League, but closer in terms of points to the relegation zone than to leaders Liverpool, who beat them 3-1 on Sunday.
- Analysis: Yesterday's man? Is Mourinho finished at the top level?
- Football Daily podcast: What next for Man Utd?
- 'Caption this', 'Do one' and other reactions to Mourinho's sacking
- Solskjaer in running for Man Utd caretaker role as Pochettino tight-lipped
The decision to sack Mourinho, which will cost more than £18m, has been taken in the long-term interests of United with a view that the club is bigger than any one individual.
Mourinho is understood to have wanted his own structure, but the new manager will be appointed with a head of football above him reporting to executive vice-chairman Ed Woodward.
A United statement said: "A caretaker manager will be appointed until the end of the season while the club conducts a thorough recruitment process for a new, full-time manager.
"The club would like to thank Jose for his work during his time at Manchester United and to wish him success in the future."
The club hope to appoint a caretaker manager before they face Cardiff City on 22 December but it will not be assistant manager Michael Carrick or academy boss Nicky Butt.
The candidate will be drawn from outside the club, but will not be former Arsenal boss Arsene Wenger.
- Prime targets and long shots: Who will be the next Man Utd manager?
- 'Take stock and reset structure' - Neville on Man Utd
A familiar conclusion to a rocky season
United's haul of 26 points after their first 17 Premier League games is their worst tally at this stage of a season since 1990-91.
They are 11 points off the top four, which would earn a Champions League qualification place.
The sacking of Mourinho, who replaced Louis van Gaal in May 2016 and signed a contract extension in January, comes after a fall-out with £89m record signing Paul Pogba, who was an unused substitute for the defeat at Anfield on Sunday.
Following a 1-1 draw with Wolves, Pogba said he wanted United to be able to "attack, attack, attack" at home, which led Mourinho to say the France midfielder would no longer be the club's "second captain".
After Mourinho was sacked, a post which said "caption this", along with a knowing expression on Pogba's face, appeared on his Twitter account before being deleted.
Former United captain Gary Neville replied: "You do one as well!"
United later claimed it was a "scheduled marketing post" by Pogba's sponsors Adidas.
Mourinho's third season did not begin well after missing out on key transfer targets in the summer, and two defeats in the first three league games - to Tottenham at home and Brighton away - meant his side were playing catch-up with the leading teams.
By October, there were reports Mourinho might be sacked prior to the home game against Newcastle, but after the team trailed 2-0, they turned it around to win 3-2 and seemingly buy the former Chelsea, Inter Milan and Real Madrid boss more time.
Mourinho's agent Jorge Mendes attempted to calm matters earlier this month by taking the step of issuing a statement to say his client was "very happy" and "fully committed" to the club.
Despite reaching the Champions League last 16, where United will play Paris St-Germain, they have won just one of their past six games in the Premier League.
Mourinho's dismissal continues his run of having never completed four consecutive seasons in charge of a club.
Only once has he made it into a fourth campaign, but he left Chelsea on 20 September 2007 during his first spell at Stamford Bridge.
Mourinho's record at United
|Manager||Games played||Won||Drawn||Lost||Goals for||Goals against||Win %|
|Louis van Gaal||103||54||25||24||158||98||52.43%|
The story of a chaotic season
- 29 July: Mourinho v pre-season tour - 'If I was the fans, I wouldn't come'
- 29 July: Mourinho v executive vice-chairman Ed Woodward - 'I gave the club a list of five names a few months ago'
- 10 August: Mourinho v Woodward part two - Manager's late attempts to sign defenders blocked
- 28 August: Mourinho v media - 'Respect, respect, respect'
- 1 September: Mourinho v Anthony Martial - Mourinho willing to let French forward leave
- 24 September: Mourinho v Pogba part one- Questions club tactics following 1-1 draw with Wolves
- 25 September: Mourinho v Pogba part two - 'No problems' but 'second captaincy' taken away
- 26 September: Mourinho v Pogba part three - Training-ground incident
- 1 October: Mourinho v the team - 'Some players care more than others'
- 20 October: Mourinho v Ianni - Touchline bust-up
- 7 November: Mourinho v Juventus fans - Did celebration go too far or show passion?
- 14 December: Mourinho v Man Utd team - Man Utd 'far' from being built in my image
- 16 December: Mourinho v Liverpool - 'Liverpool did everything better than us'
- 18 December: Mourinho sacked
Other memorable Mourinho moments:
- January 2017: Mourinho v fans - 'Don't come to the theatre'
- April 2017: Mourinho v Luke Shaw - 'He is a long way behind'
- March 2018: Mourinho v media - 12-minute speech on European record
Mourinho's United signings
Mourinho complained about the lack of new arrivals at Old Trafford, particularly in defence, during the summer.
During his time at United, he signed 11 players for a total of £358.8m.