CRTs, often known as 'lifetime legacies', are set up by people who want to give large amounts to charity but need to guarantee an income during their lifetimes. Beneficiary organisations share in the profits of the trusts and inherit the assets when the donor dies.
John Low, chief executive of the Charities Aid Foundation, said tax relief on CRTs had been rejected in the House of Lords two years ago because of fears it would be abused. But he said it had been raised again at the Giving Forum and that Lord Best, chair of the forum, had since been "charging around" promoting it, enlisting the help of former Paymaster General and major Labour Party donor Geoffrey Robinson.
Culture minister Margaret Hodge and Jane Kennedy, Financial Secretary to the Treasury, were both present at the lunch to introduce the tax relief campaign, hosted by Best.
Low said the ministers had made no commitments, but their presence at the launch was "progress in itself". He said he hoped a working party could be set up to explore the costs and benefits of tax relief, which had saved charities in the US £4bn last year and accounted for 40 per cent of all donations to education, medical and arts charities there.
"The Treasury tax group on charities is looking at efficiencies and Gift Aid as a priority," Low said. "But we are hopeful it will be willing to explore the options so that, when there is a window of opportunity, the thinking will have been done."
CRTs are also given tax relief in Australia, Canada and Germany.
The lunch coincided with a letter to The Times, whose 16 signatories included the dean of Canterbury Cathedral, the vice-chancellor of Cambridge University, the director of the British Museum and the chief executives of sector umbrella group the NCVO, the Charity Finance Directors' Group, the Association of Charitable Foundations and Philanthropy UK.
The letter read: "Giving in this way would involve a positive relationship between donor and charity and more people would be encouraged to participate, because they would see the benefits of their giving during their own lifetime.
"We urge the Chancellor to include an evaluation of lifetime legacies in the Pre-Budget Report this November, with a view to its inclusion in his Budget next year."