Advertising mogul Sir Martin Sorrell has been urged not to speak at a conference promoting trade between Europe and Iran because of the Middle East country’s “antisemitic” and “anti-Israel” government.

Groups including the Zionist Federation (ZF) wrote an open letter to Sir Martin, who owns advertising giant WPP, asking him to reconsider attending the two-day forum in London.

The ZF has joined with grassroots pro-Israel groups NILI14, the Israeli Forum Task Force and UK Friends of Israel in calling on him to renounce the “extremist regime”.

The activists say they “struggle to understand why you would speak of trade with one of the world’s most violent and theocratic regimes, with a long history of antisemitism and which does not hide its anti-Israel sentiments.”

The groups also accuse Iran of executing and assassinating “more than 120,000 Iranian citizens since 1979” and funding terrorist organisations such as Hizbollah and the Taliban.

The event at Grosvenor House, which will also include a speech from former foreign minister Jack Straw, asks how Europe can benefit when sanctions on Iran are lifted.

Activists are planning to hand out flyers outside the forum.