Her decision to resign as International Development Secretary came after being summoned back from an official visit to Africa for a showdown with Theresa May in Downing Street.
Ms Patel, a Brexit campaigner who was popular in Ms May's Government, headed back to London yesterday after cancelling a planned trip to Africa to respond to the reports that she failed to declare meetings with Israeli officials in a breach of diplomatic protocol.
May, in her response, said: "Now that further details have come to light, it is right that you have chose to resign and adhere to the high standards of transparency and openness that you have advocated".
On Monday, Patel had apologised for failing to disclose meetings with senior Israeli officials during a private holiday.
In her letter to Theresa May, Ms Patel said: "While my actions were meant with the best of intentions, my actions also fell below the standards of transparency and openness that I have promoted and advocated".
"I can see how my enthusiasm to engage in this way could be mis-read, and how meetings were set up and reported", Patel said in a statement.
It was not clear who would replace Patel, who held the meetings during a holiday in Israel earlier this year.More news: Avs get haul for Duchene in blockbuster trade
She apologized, but it has since emerged that she also met in September with Israeli public security minister Gilad Erdan and a foreign ministry official.
According to the Press Association, Downing Street was told about the NY breakfast with Rotem when Patel revealed the details of her trip to Israel, but only learnt on Tuesday about the meeting in Parliament with Erdan. "The foreign secretary did become aware of the visit, but not in advance of it". "I am sorry for this and I apologize for it".
Former Conservative foreign secretary Malcolm Rifkind told BBC the meeting were "extremely unwise", adding: "Not only did she not tell the Foreign Office directly, so far as I'm aware the British Embassy in Israel wasn't aware that this was happening".
Had she not resigned, Patel would nearly certainly have been fired.
It emerged that Patel had visited an Israeli military field hospital in the Golan Heights even though Britain has never recognized Israeli control of the area seized from Syria in the 1967 Six-Day War.
Labour has already demanded an investigation into Patel's meetings with the Israeli government, claiming they involved four "serious breaches" of the ministerial code.
"The prime minister met the secretary of state this morning to remind her of the obligations which exist under the ministerial code".
No 10 denies it instructed Ms Patel not to publicise the September meeting with Yuval Rotem, the diplomat, to avoid embarrassing the Foreign Office, but accepts it knew about it.