The leader of the Labour Party Jeremy Corbyn has written to Prime Minister Theresa May urging her to investigate “improper interference in this country's democratic process," by Israeli officials, it has been reported.

Shai Masot, Israeli embassy employee, was recorded as part of a four part documentary for Al-Jazeera, discussing his intention to “take down” British MPs including Sir Alan Duncan, the Foreign Office Minister.

The secret filming led to a major row between pro-Israel groups and diplomats over how an undercover reporter was able to infiltrate private meetings.

In a letter to Ms May, the Labour leader is believed to have described the actions of Mr Masot as "improper interference in this country's democratic process". 

He added he was "concerned" UK foreign minister Boris Johnson believed the matter was closed. 

And called on the Prime Minister to take further action. 

He wrote: "This is clearly a national security issue.

“It is only on [the basis of an investigation] that Parliament and the public will be reassured that such activities will not be tolerated by your government." 

The documentary was widely criticised by community leaders. 

It is believed the undercover reporter working for Al-Jazeera may be the subject of a legal complaint over his treatment of Jewish Labour activist Ella Rose.

The reporter used the false identity “Robin Harrow” to make contact with Jewish groups while working on the documentary, called The Lobby, on Israel’s alleged influence in British politics.

In the second episode he is seen secretly filming Ms Rose, the director of the Jewish Labour Movement, who appears to be in tears following an encounter with Jackie Walker, a Labour activist twice suspended over claims of antisemitism.

A senior Jewish Labour source told the JC: “There are other elements of Harrow’s behaviour towards [Ella Rose] whilst undercover that we have not been able to speak about publicly as, pending advice, we hope they will become the subject of a legal complaint.”