Labour MP Catherine West has threatened to launch a leadership challenge against Sir Keir Starmer.
She says she doesn't want the job herself, but after a "disastrous" set of elections for the party, she thinks "new leadership" is required "which understands the urgent and real concerns of people across the UK".
She wants someone in the cabinet to come out and challenge Sir Keir - but if no one does by Monday, she'll canvas for the 81 backers she needs to launch a formal challenge.
So who is Catherine West?
West was first elected to parliament in 2015 in the constituency of Hornsey and Wood Green - now Hornsey and Friern Barnet - in north London.
An Australian, West was born in the town of Mansfield, 110 miles northeast of Melbourne, and moved to London in 1998 when her husband got a job at the London School of Hygiene and Tropical Medicine.
She speaks five languages including Mandarin, which she developed while teaching English as a second language in Nanjing, China.
Before moving to London, she worked as a social worker at a refuge for survivors of child sex abuse in Darwin, northern Australia.
She worked as parliamentary case worker for now-Deputy Prime Minister David Lammy when he was first elected as an MP in 2000.
West was later elected as a Labour councillor in Islington, also north London, in 2002, after Mr Lammy persuaded her to stand.
She served on the council for 12 years and was council leader from 2010 to 2013.
After being elected to parliament, she served as a shadow foreign minister under Jeremy Corbyn - but was sacked after defying the whip to vote for the UK to remain in the European single market after Brexit.
She became a shadow foreign minister again when Starmer became Labour leader in 2020, and was appointed as junior minister for the Indo-Pacific in 2024.
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In that role, she was once again reunited with her former boss David Lammy, who was foreign secretary at the time.
West left government last September when the prime minister reshuffled his ministerial team following the resignation of Angela Rayner from government over her tax affairs.
Since leaving government, she has kept a lower profile, serving as a trade envoy to Pakistan - until now, as she threatens to push Labour headfirst into a leadership race.
(c) Sky News 2026: Who is the Labour MP threatening to oust Starmer?
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