Diane Abbott has been replaced as Labour's shadow home secretary to cover what the party has called "a period of ill health."
Abbott has been replaced by Lyn Brown, previously the shadow policing minister. It is unclear whether the change is permanent.
Labour leader Jeremy Corbyn, a long-standing ally of Abbott, has repeatedly been asked whether Abbott will be given the Home Office if the party win power, but has not done so.
Pushed on the issue today (Wednesday), he only said she had "done a good job" according to The Independent.
News of Abbott's replacement is likely to prompt considerable criticism among Conservatives, given that it comes just a day before polling opens for the general election.
The Tories have focused much of their attention on Abbott in recent weeks, believing her a weak link in Corbyn's shadow cabinet.
Abbott has made a number of embarrassing gaffes in recent weeks, notably her failure to remember the key costs of Labour's flagship policing policy and her failure earlier this week to remember the details of a leading report into terrorism.
However there has been no suggestion until now that Corbyn was planning to replace her.
Brown, meanwhile, has served as the MP for West Ham since 2005. She was first appointed to the shadow home affairs bench in 2015, but resigned in 2016 following a vote of no confidence in Jeremy Corbyn. She has also admitted Corbyn was not her "first choice" as Labour leader.
She was then given her current role as the shadow policing minister, rejoining the front bench.
Policing and national security has become a frontline election issue, in the wake of three deadly UK terror attacks in three months.