The Labour party has called on the government to immediately launch an inquiry into “improper interference in our democratic politics” after the disclosure that an Israeli embassy official had plotted to “take down” UK MPs regarded as hostile.

The shadow foreign secretary, Emily Thornberry, said: “The exposure of an Israeli embassy official discussing how to bring down or discredit a government minister and other MPs because of their views on the Middle East is extremely disturbing.”

The Israeli ambassador, Mark Regev, has apologised to one of the MPs on the “hit list”, foreign office minister Sir Alan Duncan, describing the remarks as unacceptable. As a result, the Foreign Office said it regarded the matter as closed.

But Thornberry said: “It is simply not good enough for the Foreign Office to say the matter is closed. This is a national security issue.” As well as calling for an inquiry, she said the embassy official should be withdrawn.

The official, Shai Masot, who describes himself as a senior political officer, was caught on camera in an undercover sting by a reporter from the al-Jazeera investigative unit.

The embassy said Masot would shortly be ending his term of employment with the embassy. Masot had been speaking to Maria Strizzolo, a civil servant who was formerly an aide to another Conservative minister. Sources at the Department for Education said on Sunday they understood Strizzolo had resigned from her civil service post.

The revelations also provoked anger among many Conservative politicians. One former minister in David Cameron’s government said the embassy’s efforts to exert improper influence on British public life went far further than any plot to “take down” unhelpful members of parliament.

Writing anonymously in the Mail on Sunday, the former minister said: “British foreign policy is in hock to Israeli influence at the heart of our politics, and those in authority have ignored what is going on.

“For years the Conservative Friends of Israel (CFI) and Labour Friends of Israel (LFI) have worked with – even for – the Israeli embassy to promote Israeli policy and thwart UK government policy and the actions of ministers who try to defend Palestinian rights.

“Lots of countries try to force their views on others, but what is scandalous in the UK is that instead of resisting it, successive governments have submitted to it, take donors’ money, and allowed Israeli influence-peddling to shape policy and even determine the fate of ministers.”

The former minister said there needed to be a full inquiry into the Israeli embassy’s links with CFI and LFI, and that while political parties should welcome funding from the UK’s Jewish community, they should not accept any engagement linked to Israel until it ceases new developments on Palestinian land.

“This opaque funding and underhand conduct is a national disgrace and humiliation and must be stamped out,” the former minister wrote.