Alastair Cook has been removed as England one-day captain and replaced by fellow batsman Eoin Morgan, less than two months before the World Cup.
Cook, 29, who was appointed to lead the one-day side in 2011, averages only 27.52 in his last 20 one-dayers.
During the recent 5-2 series defeat in Sri Lanka, Cook insisted he would not resign, but a selectors' meeting on Friday took the decision for him.
Morgan began his career with Ireland and has played 107 ODIs for England.
The 28-year-old left-hander, however, is in a similarly poor run of form, averaging only 25.45 in his last 23 matches.
|Alastair Cook as England one-day captain|
The end of Cook's reign as one-day skipper comes at the end of a turbulent year for the opener, in which he has presided over a 5-0 Ashes series defeat, the ending of Kevin Pietersen's international career and calls for him to stand down as Test captain.
He did turn around his five-day form and the fortunes of his side with a 3-1 Test series win over India, but pressure on Cook's position as ODI skipper increased with a 3-1 home one-day series defeat by the same opponents and the unsuccessful tour of Sri Lanka.
Although England and Wales Cricket Board managing director Paul Downton said he would be "surprised" if Cook were replaced before the World Cup, he did not have a vote on the four-man selection panel.
Meanwhile, coach Peter Moores, a selector alongside James Whitaker, Mick Newell and Angus Fraser, refused to guarantee that Cook's place as World Cup leader was secure.
This came against the backdrop of a host of former England captains - including Nasser Hussain, Alec Stewart and Michael Vaughan - calling for Cook to be replaced as captain.
Vaughan told BBC Radio 5 live on Friday evening that Cook "knew he shouldn't be in the team" in Sri Lanka.
Essex batsman Cook took charge of the one-day side after the 2011 World Cup, continuing a sequence that has seen England replace their limited-overs skipper after each of the last four tournaments.
He enjoyed some initial success, taking England to the top of the world rankings in 2012, a year in which he scored three ODI centuries.
However, after leading England to defeat by India in the final of the Champions Trophy in 2013, Cook has not since presided over a series victory.
|Twitter reaction to Cook's departure|
|Michael Vaughan, ex-England captain: Right call made by England... Now I hope Cook can have a good break and then come back in the summer as the Test player we know he can be... Congrats @Eoin16... The right man for the job....|
|Kevin Pietersen, ex-England international: Great news that @Eoin16 is new England one-day captain. Top player, leader and bloke. Hope I get to play for him.|
Dublin-born Morgan made his one-day international debut for his native Ireland in 2006, but switched to represent England three years later.
He has regularly deputised as captain in limited-overs cricket, most recently in the fourth one-dayer in Sri Lanka when Cook served a one-match ban for a slow over-rate.
In his eight matches as skipper Morgan averages 71.16, while England have won on three occasions when the left-hander has led the side.
While England have often split captaincy of their various teams in the past - Stuart Broad is the current Twenty20 leader - Morgan represents a low-risk threat to Cook's position as Test skipper because he is not currently part of the five-day set-up.
Morgan will now lead England into a tri-series against Australia and India, and the subsequent World Cup down under, the squad for which will be confirmed on Saturday morning at 11:00 GMT.
Pietersen, who is playing for Melbourne Stars in Australia's Twenty20 competition the Big Bash League, tweeted: "Great news. Top player, leader and bloke. Hope I get to play for him."
Alex Hales and Ian Bell are the candidates to replace Cook as Moeen Ali's partner at the top of the order, with Yorkshire's Gary Ballance a leading candidate to take his place in the squad.
England begin their World Cup campaign against co-hosts Australia on 14 February in Melbourne.
|England's recent World Cup record|
|2011||Quarter-finals||Andrew Strauss||India, Sri Lanka & Bangladesh|
|2007||Super Eights||Michael Vaughan||West Indies|
|2003||First group stage||Nasser Hussain||South Africa|
|1999||First group stage||Alec Stewart||England, Wales, Scotland & Ireland|
|1996||Quarter-finals||Mike Atherton||Pakistan, India & Sri Lanka|