Al Jazeera did not breach any broadcasting rules in its coverage of the pro-Israel lobby in the UK, Britain's broadcasting regulator has ruled.

On Monday, Ofcom dismissed complaints against Al Jazeera's four-part series "The Lobby", an undercover investigation that aired in January and made global headlines.

Filmed over six months, The Lobby revealed the Israeli embassy's covert influence campaign to smear and attack British citizens critical of Israel and its practices - including British Foreign Office Minister Sir Alan Duncan.

Ofcom received complaints in the aftermath of the series from a number of pro-Israeli British activists, including one former Israeli embassy employee.

These complaints levelled a range of charges against Al Jazeera from "anti-Semitism" and bias to unfair editing and infringement of privacy.

In each instance, Ofcom dismissed the charges, and the complaints as a whole without reservation.

"We did not consider that this aspect of the complaints warranted further investigation," Ofcom said.

"The fact that the programmes uncovered evidence of inappropriate behaviour by those acting on behalf of the Israeli government, or by those belonging to a small number of organisations that promote Israeli policy, does not mean that they were anti-Semitic," Ofcom said. "In the same way, programmes that expose the violence associated with some black gang culture in Britain’s inner cities are not, by default, racist."

Ofcom is a government-appointed body that regulates all broadcasting media in the UK with wide-ranging, statutory powers.

It maintains journalistic standards and ethics and presides over conduct and policies for programme makers.

"We are extremely pleased with the verdict," said Clayton Swisher, Al Jazeera's director of investigative journalism and the series narrator. "It overwhelmingly validates the revelations captured by our brave undercover, known as 'Robin'. Our entire team put a ton of care into making this film, under full legal review throughout. This totally vindicates our work and is a terrific verdict for all journalists exposing wrongdoing."

Undercover investigation

As part of the investigation, Al Jazeera filmed Shai Masot, the Israeli embassy's then senior political officer.

At one point, in a discussion with British civil servant Maria Strizzolo, Masot plotted to "take down" Sir Alan Duncan, a vocal supporter of Palestinian rights who has condemned the Israeli occupation.

Masot's position came to an early end shortly after the investigation was broadcast. Strizzolo resigned.

The Israeli ambassador to Britain, Mark Regev, formally apologised to the British Foreign Office while Foreign Secretary Boris Johnson conceded Masot's "cover" was "well and truly blown".

Ofcom's findings come at a time when Israel is seeking to close Al Jazeera's Jerusalem bureau and deny its reporters access for allegedly causing "incitement".

Meanwhile, at least four Arab states are demanding the wholesale closure of Al Jazeera amid a blockade against Qatar, where Al Jazeera is based.

The Lobby is available to watch here.