Hawzah News Agency (UK)-Israel is attempting to smear activists who question the illegal occupation of Palestinian land by helping to build racism cases against them, an investigation by Al Jazeera's Investigative Unit reveals.

The investigation, "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 (alias), an undercover reporter, 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 Shai Masot, a senior policial officer at the embassy.

Robin posed as a graduate activist with strong sympathies towards Israel who was keen to launch a pro-Israel youth group within the opposition Labour Party and help combat the Boycott, Divestment and Sanctions (BDS) movement.

In September, Masot took Robin to the 2016 Labour Party conference in Liverpool. On the sidelines, Mike Katz, vice chairman of the Jewish Labour Movement, held a training session regarding anti-Semitism, which Al Jazeera filmed secretly.

Some Labour members who raised questions over the definition of anti-Semitism, and were soon accused of racism.

When the discussion moved to the subject of Zionism, the political ideology that Israel has the right to exist as an exclusively Jewish homeland in historic Palestine, some attempted to debate the issue.

"Anti-Semitism, like any form of racism is deplorable and my feeling about how to tackle this is for Jews to be standing firmly and squarely alongside our black comrades, our Muslim comrades, who are much more at the moment the target of racism thankfully [than] we are," said leading Labour activist Jackie Walker, a black British Jew.

She added that she hadn't "heard a definition of anti-Semitism [within the session] that I can work with" and concluded, "If you are saying effectively that Zionism is not open to debate as a concept, then that is really worrying."

Walker soon faced threats and criticism.

Footage of her comments appeared on the internet and news of the event hit British newspaper headlines the following day. She was later suspended from the Labour Party pending an investigation and lost her role as vice-chair of Momentum, a left-wing organization supportive of Labour leader Corbyn.

When Robin asked Masot about Walker, the Israeli diplomat said: "She is problematic".

"Do not let it go," he advised, and urged Robin to report "all of the party" members who make similar comments.