Sajid Javid
Here's a look back at the last week to see what might have put the prime minister in a precarious position.
Meanwhile, Steve Barclay is made health secretary following Sajid Javid's departure.
Nadine Dorries and Jacob Rees-Mogg are still backing the under-fire prime minister.
Chancellor and health secretary are the first ministers to quit amid Tory unease over the Chris Pincher affair.
Health secretary Sajid Javid blamed the delay on the Covid backlog.
"They say they've unearthed evidence of you avoiding hundreds of thousands of pounds in tax before you got into politics, did you?"
The prime minister is facing growing backlash from within his own party over his time in Downing Street.
Following the PM's resignation, here's a look at the Tory leadership runners and riders – including Liz Truss and Nadhim Zahawi
The issue has sparked fury from Tory MPs who have called on the government to "have some empathy".
The change to allow medical abortions at home following a phone or video consultation was introduced during lockdown.