Ministers, by convention, should tell the Foreign Office when they are conducting official business overseas.
A British minister has apologised after misleading the public about secret meetings she had with the Israeli government organised by an influential pro-Israeli lobby group in the UK.
It was confirmed that Ms Patel did not reveal her meetings only afterwards.
Global development secretary Priti Patel has admitted foreign secretary Boris Johnson did not know about her trip to Israel until she was there - and revealed a slew of meetings not previously disclosed.
A senior Conservative told The Daily Telegraph: "She had a week full of meetings without officials and without contacting the embassy. There is no United Kingdom financial support for the Israeli army", a Downing Street spokesperson said after it emerged that in the wake of her visit in August, Patel had discussed potentially providing some of Britain's aid money to Israel's armed forces which run field hospitals in the Golan Heights area.
A senior British minister on Monday admitted that she held a previously undisclosed meeting with Israeli Prime Minister Benjamin Netanyahu while on holiday in Israel in August.
"Patel has a history of showing favouritism to Israel and is suspected to cut or divert the essential aid that the United Kingdom sends to the Palestine Authority", Slaughter told MEE.
Patel's apology statement included a list of people she met, along with a brief summary of the discussions.
Another senior Cabinet minister, Foreign Secretary Boris Johnson is also in the eye of a storm after he made comments which have left a British citizen, Nazanin Zaghari-Ratcliffe, imprisoned in Iran facing a sentence twice as long as it now is.
Kate Osamor, the shadow worldwide development secretary, told the Commons on Tuesday that it was "hard to think of a more black and white case of breaking the ministerial code of conduct".
Patel also conceded that comments she gave last week, in which she suggested Boris Johnson had advance knowledge of the trip, may have given the wrong impression. While away, I had the opportunity to meet a number of people and organizations.
"She saw the Israeli prime minister with a donor lobbyist, and failed to declare or admit to the meetings".
"I don't know what was in her mind when she said that".
Such meetings could constitute a violation of Britain's ministerial protocol.
The statement added that the Foreign Office was aware of the visit while it was underway, but was not informed about it in advance. In any ordinary circumstances a member of government embarking on a secret diplomatic mission and holding unauthorised talks with a foreign power would be an instant firing offence.