Theresa May's government has been plunged into a fresh crisis after the second Cabinet minister in a week was forced to resign.
Priti Patel has quit her position as international development secretary, just days after defence secretary Michael Fallon also stepped down.
Patel was this morning summoned back to London from an official trip to Africa after a second set of undisclosed meetings with Israeli officials surfaced. Following a brief meeting at Number 10, Patel handed in her formal resignation.
Her letter to the Prime Minister said her recent actions had "served as a distraction" from her department "and of the government as a whole".
The Witham MP said she had acted "with the best of intentions" but accepted it "fell below the standards that are expected of a secretary of state" and "of transparency and openness that I have promoted and advocated".
"I offer a fulsome apology to you and the government for what has happened, and offer my resignation," Patel wrote.
In her acceptance letter, May said it was "right" that the UK had close ties with Israel, but said "that must be done formally, and through official channels".
While an apology had sufficed originally, May added: "Now that further details have come to light it is right that you have decided to resign and adhere to the high standards of transparency and openness that you have advocated".
Patel held 14 undisclosed meetings with Israeli figures, including Israeli Prime Minister Benjamin Netanyahu, who May held a bilateral with last month before knowing about Patel's own meetings.
Although she had apologised for those held during a summer holiday to Israel, it transpired last night that Patel had held additional unsanctioned meeting in London with Israel's public security minister Gilad Erdan on 7 September, and one in New York with a foreign office official Yuval Rotem on 18 September.
Yesterday, Patel's colleague Alistair Burt told MPs that she had informed the foreign office on 24 August - after most of the meetings had taken place. It was also confirmed that she had suggested aid be given to the Israeli Defence Force in the Golan Heights, to help with its humanitarian efforts in working with Syrian refugees.
Patel's fate was delayed by an eight and a half-hour journey back from Nairobi today. At points 22,000 people were watching her flight progress over the continent and across Europe before landing just after 3pm this afternoon.
it follows defence secretary Fallon's resignation last week in the wake of allegations of sexual misconduct.
And the erosion of the Cabinet might not stop there. Calls are growing for foreign secretary Boris Johnson to step down after his comments on British-Iranian national Nazanin Zaghari-Ratcliffe, who he described as "simply teaching journalism" - a crime in Iran and something strongly denied by both her husband and employer.
Meanwhile an investigation is ongoing into allegations that Damian Green, the Prime Minister's closest ally, had "extreme porn" on computers found in his office during a police raid several years ago. May's number two denies the allegations.
Conservative MPs have backed the move, despite its potentially destabilising impact.
Nicky Morgan told City A.M: "I'm personally sorry for Priti. Ministers pay a high price for their mistakes."
But she added: "Patience [is] running out for the PM."
James Cleverly tweeted that Patel was: "a committed local MP, passionate Conservative, and longstanding friend but she made an error of judgment and did the right thing by standing down."
Anna Soubry said the Prime Minister should go further and "assert her authority [with a] thorough reshuffle".
It is not yet known who will replace Patel in Cabinet.