The Al Jazeera documentary aiming to uncover links between the Israeli embassy and British political and student groups is the subject of a formal investigation by the media watchdog Ofcom.

The Lobby – which aired on the Qatari-owned channel in January – was already the subject of four separate complaints over its allegation that Israel’s UK embassy was trying to influence groups such as the Labour Friends of Israel and the Jewish Labour Movement.

In the latest round-up of television complaints, published on Monday, it was confirmed that The Lobby is now the subject of a formal investigation in two categories – breaches of content, and fairness and privacy.

“We are investigating whether this programme complied with our rules on due impartiality and offence, and whether it materially misled the audience,” an Ofcom spokesman confirmed.

The Jewish Leadership Council was one group known to have written to Ofcom to lodge a complaint about The Lobby. Pro-Israeli campaigner Jonathan Hoffman was another to have registered a complaint.

Simon Johnson, chief executive of the JLC, said: “The JLC has today, acting on behalf of its employees, and employees of its member organisations, filed a formal complaint with Ofcom in respect of the Al Jazeera programme The Lobby. The complaint alleges that the programmes on Al Jazeera infringed the Ofcom code in relation to fairness, privacy and due impartiality.”

The latest edition of the official TV complaint bulletin lists complaints to Ofcom that have been assessed and deemed not been in breach of strict guidelines – as well as those which may have a case to answer.

The Lobby is listed as one show that is being investigated. But Ofcom stresses that a formal investigation does not necessarily mean the broadcaster has done anything wrong.

The documentary featured recordings obtained by an undercover reporter of former  junior Israeli embassy employee Shai Masot, who is heard joking about  “taking down” MPs critical of Israeli settlements. It prompted a number of questions in the House of Commons, with Speaker John Bercow describing it as a “serious concern”.

The documentary also led to the resignation of Maria Strizzolo, a former chief of staff to MP Robert Halfon, the deputy Conservative Party chairman.

Israeli Ambassador Mark Regev apologised to Foreign Office Minister Alan Duncan.

Mr Hoffman told the JC on Monday: "Most complaints to Ofcom do not move to formal investigation stage. The news that this one has - moreover in two categories - is therefore very welcome."