An Israeli political officer, who was at the centre of an Al Jazeera investigation, has been forced to resign from Israel's UK embassy, a senior official in the Israeli foreign ministry has told Al Jazeera.

Shai Masot, a senior political officer working at the Israeli embassy, resigned from his post earlier this week, the spokesman said on Thursday.

The investigation, The Lobby, reveals plots by the Israeli diplomat and a British civil servant to destroy the careers of senior politicians.

In a statement posted on his Twitter account on Sunday, the UK Israeli embassy's spokesman, Yiftah Curiel, downplayed comments made by Masot.

"The Embassy of Israel rejects the remarks concerning Minister [Sir Alan] Duncan, which are completely unacceptable; the comments were made by a junior embassy employee who is not an Israeli diplomat, and who will be ending his term of employment with the embassy shortly."

The Lobby also uncovers Israel's extensive, well-financed propaganda campaign in the UK to counter negative news stories about its policies and to fund trips to Israel for young activists.

As part of a six-month investigation, Robin, an undercover reporter using an alias, infiltrated a lobby of politicians, activists and Israeli embassy officials working to drum up support for Israel.

Many enjoyed financial or strategic support from the Israeli embassy in London via Masot.

Israel's apology

The Israeli embassy has apologised to UK deputy foreign secretary Sir Alan Duncan for comments made by Masot on plans "to take [him] down" due to his criticism of Israel's settlement activity in the occupied West Bank.

In a conversation with Maria Strizzolo, who was then chief of staff to MP Robert Halfon, the deputy chairman of the ruling Conservative Party, Masot asked her if he could give her some names of MPs he would suggest she "take down".

Masot named Duncan, who in 2014 said that while he fully supports Israel's right to exist, he believes settlements on occupied Palestinian land represent an "ever-deepening stain on the face of the globe". He also likened the situation in Hebron in the occupied West Bank to apartheid.

Strizzolo later hinted that "a little scandal" might see Duncan dismissed.

But this latest disclosure is just one among the Investigative Unit's many findings, which are being revealed in The Lobby, a four-part series that is be broadcast daily on Al Jazeera from January 11 at 22:30 GMT.

The undercover investigation reveals how the Israeli government is in the midst of a brazen, covert influence campaign in Britain.

For half a year, Robin, an undercover reporter working with Al Jazeera's Investigative Unit, met members of Britain's lobby network that enjoys strong support from the Israeli government by way of the Israeli embassy in London.

Robin posed as a graduate activist with strong sympathies towards Israel who was eager to help combat the Boycott, Divestment and Sanctions movement prominent in Britain.

Al Jazeera Investigative Unit's series "The Lobby" can be viewed on Al Jazeera:

Episode One: Young Friends of Israel - Available online

Episode Two: The Training Session - Available online

Episode Three: The Anti-Semitic Trope - Friday, January 13, 22:30 GMT

Episode Four: The Takedown - Saturday, January 14, 22:30 GMT

The series will also be available online.