The Treasury is very keen to dispel the notion that the proposed tax relief cap is at all motivated by the cost to the Exchequer of tax reliefs on charitable giving and the need to tackle the national deficit.

After civilsociety.co.uk ran a story earlier this week highlighting the escalating costs of gift aid and tax relief on donations by higher-rate taxpayers, the Treasury got in touch to insist that this is not the driver for the tax cap proposal.

A spokeswoman said that the cap is motivated primarily by the need to address the unfairness of a situation where a few very wealthy citizens pay significantly less tax as a proportion of their income than ordinary people.

She said: “There are currently millionaires paying a lower tax rate than ordinary taxpayers. This is the system we have at the moment, but the government is committed to making it fairer.

“The Budget makes clear that we want to ensure genuine charities that rely on large donations are not hit significantly, which is why we said we’d spend time working with the charity sector and philanthropists on the details.”

Since the Chancellor first announced the cap in March, various government sources have offered a number of reasons for it.  As well as the fairness argument cited by the Treasury above, reasons have included preventing people from slashing their tax bills by giving to bogus charities abroad, and the need to tackle the national debt.

This latter argument came from Economic Secretary to the Treasury, Chloe Smith, at a Charity Tax Group conference last week.  But the Treasury spokeswoman said that Smith’s comments about the deficit were “more nuanced than saying that this is just revenue-raising”, and in fact if read in full, support the fairness point.

Smith said in her speech: “In the end, the best way that we can support the families, those on low incomes, and the most vulnerable in society is by ensuring that we restore our economic prosperity.

“First and foremost that means tackling our deficit. But even as we undertake that task we are committed to doing so in a fair way. We will not let the poor and the vulnerable carry the burden of deficit reduction. It is fair that those who have the most, contribute the mot, and that means ensuring people continue to contribute their fair share through tax revenues.

“We will continue to encourage charitable giving through tax reliefs, but it is fair that we cap the amount of relief available.”