Reform UK’s deputy leader Richard Tice is being investigated by the parliamentary standards watchdog over an allegation he failed to declare an interest.

The investigation was opened on Tuesday 28 July and was published on the Parliamentary Standards Commissioner website on Monday.

Tice said the complaint related to a Commons debate about Israeli influence and whether he should have referenced his register of interests.

Reform said Tice did not mention in his 22 June speech that he had been on a trip to Israel last September, funded by a pro-Israel lobbying group.

The trip has been listed in Tice’s Declaration of Members’ Interests., external

The investigation relates to Rule 6 in the parliamentary code of conduct, which states: “Members must always be open and frank in declaring any relevant interest in any proceeding of the House or its committees, and in any communications with ministers, members, public officials or public office holders.”

The Parliament’s guidance to the code of conduct states that MPs can refer to their entry in the register of interests but adds: “Such a reference will not suffice on its own, as the declaration must provide sufficient information to convey the nature of the interest without the listener or the reader having to have recourse to the Register or other publication.”

Separately, an investigation has also been opened into DUP MP Sammy Wilson, for an allegation of failure to declare an interest. The DUP has been contacted for comment.