Technical director Stephen Maguire has left UK Athletics “with immediate effect”.
Maguire, 59, led Britain to their joint-best medal haul of 10 at August’s World Athletics Championships, matching their 1993 performance.
The chief selector had been in the post for 16 months, and departs nine months before the Paris 2024 Olympics.
British sprinter Dina Asher-Smith said she would like a “full explanation” for the “disappointing decision”.
Northern Irishman Maguire has previously worked at Sport Ireland and Sport Scotland and took over UK Athletics’ most senior coaching position after Christian Malcolm’s exit in June 2022.
UK Athletics said: “An interim head coach will be announced in due course. Until then no further comment will be made.”
Former world champion Asher-Smith said in a post on Instagram: “Stephen has been phenomenal, so dedicated and has an excellent understanding of what it takes to be successful in the sport of track and field.
“Such a snap decision as athletes begin to prepare for an Olympic Games cannot have been done with any consideration for the performance needs of the athletes.
“As an athlete, it would be nice to have this explained to us, as much as any confidentiality clauses allow of course, because from the outside looking in it seems like an incredibly short-sighted decision made without considering that we are in an Olympic year.”
