Duncan Smith, who resigned from the Cabinet in a row over cutting disabled benefits in the Budget, has been invited to attend the event in Tel Aviv, which runs from June 6.

He is one of a number of senior government figures keen to quit the European Union, a topic that will be a key feature at the conference.

ITT chairman Steven Freudmann said: “We have approached him and are waiting for a reply.”

The referendum takes place on June 23, little more than a fortnight after the ITT’s conference, which will stage a roundtable EU debate on the final day. One participant already signed up is Lord Cashman, who was a former member of the European Parliament as well as being a gay rights campaigner and former EastEnders actor.

Freudmann said Cashman would speak for the “In” lobby and that he hoped Duncan Smith would lead the “Out” side of the discussion.

Several other key speakers have now been confirmed, including Nick Longman, the Tui UK and Ireland managing director and Suzanna Chiu, head of Amadeus Ventures, who will discuss the criteria used in assessing and valuing potential acquisitions.

There will also be a discussion on world events as they impact the industry. This will be a joint presentation from David Smith, chief executive of Global Futures and Foresight and Professor Graeme Leach, chief economist and director of policy at the Institute of Directors.