A Tory donor’s campaign to force the government to hold a referendum on the European Union’s Lisbon treaty will on Monday step up a notch, with the release of polling data suggesting most people believe the government has reneged on its pledge to give them a vote on the issue.

The survey comes a week before the High Court starts hearing a legal challenge brought by Stuart Wheeler against the government’s refusal to hold a referendum. Next week will also see the crucial Irish referendum on whether to ratify the contentious treaty.