Their wealth may be falling but the amount they are giving away continues to rise. Britain’s leading philanthropists are spending their way through the recession, according to figures in this year’s Sunday Times Giving List .

All talk in the economy is focused on providing “fiscal stimulus”, and those in the Rich List have taken a similar approach to their charitable activities.

Despite a 37.5% fall in the wealth of the leading 1,000 this year, the top 100 philanthropists have put £216m more into charity than last, bringing their spend to a record £2.817 billion, up 8% on 2008.

There have been some huge transfers of assets from wealthy givers seeking to preserve the bottom line for their charitable foundations as the stock market decline erodes the funds that underpin much charity work.

The Sainsbury family, for example, injected almost £340m into its charitable vehicles in the year to March 31, 2008, and gave out grants of about £67m. Lord (David) Sainsbury invested £181m in the Gatsby Charitable Foundation, the biggest of the Sainsbury trusts. Despite this, its asset base rose only £84m during the year to £465m. Even allowing for the nearly £31m of grants distributed, it shows how seriously the recession is undermining charities’ assets.

Evidence suggests, however, that the renowned altruist Sir John Madejski was wrong to say that a “tap has been switched off”. Speaking shortly after he was knighted at Buckingham Palace last month, he said: “It’s going to be a big struggle for institutions that rely on giving because of the economic downturn.”

Our top 30 givers have donated at least 4.5% of their wealth in the past year. In 2008, the minimum donation required to make the top 30 was 3%, also a substantial rise on the 1.36% needed in 2007.

This year’s further increase in the proportion of wealth given away cannot be attributed just to a drop in philanthropists’ wealth (against which we measure levels of donations to produce our Giving Index). Year-on-year comparison of the 30 biggest donations, irrespective of the donors’ wealth, also shows a significant increase of nearly 9%, from £2.357 billion in 2008 to £2.565 billion.

“It’s important that charities do not talk themselves into recession,” says Dr John Low, chief executive of the Charities Aid Foundation, our partner in producing the Giving List. “Income in some areas is sagging but mechanisms such as trust funds will keep the flow of cash going.

“Charities have become less bureaucratic and fleeter of foot. They can often see a need and a way of meeting the need that does not necessarily involve having to be given more money.”

There is, of course, a time lag in our survey. Most of the charity accounts examined have been published in the past 15 weeks and relate to the financial year ending on April 5, 2008. The financial crisis has deepened since then, but the warning signs were clear a year ago with the shrinking of many charitable trust asset bases.

In that sense, the rise in capital-gains tax last April could not have come at a better time for the many charities and trusts reliant on benefactions from high-net-worth individuals. On the eve of the change, Lord Sainsbury moved 8m supermarket shares to the Gatsby Foundation and 92m shares to Innotech Advisers, a Sainsbury-owned company that donates its profits to charity.