The UK Statistics Authority – which polices the use of stats by politicians and civil servants – has lost patience with the Vote Leave campaign and its most prominent economic claim: that membership of the European Union costs Britain £350 million a week.

On 21 April the UK Statistics Authority, which is chaired by Sir Andrew Dilnot, criticised the use of this figure as inaccurate, since it takes no account of the special “rebate” that the UK receives on its annual contribution to the EU budget or the money that Britain’s farmers and some other areas of the UK are paid from those funds.

But the Leave campaign and its main figureheads including Boris Johnson and Nigel Farage have ignored this ruling and continued to publicise the £350 million figure relentlessly in Leave posters, websites and events. It's even emblazoned across the campaign’s official “battle bus”.

A further intervention from the UK Statistics Authority today signals it has lost patience with Leave’s tactics and though it has no legal power to prevent the campaign from making the claim it wishes to make clear to the voting public that the Leave figure is not to be trusted.

“The UK Statistics Authority is disappointed to note that there continue to be suggestions that the UK contributes £350 million to the EU each week, and that this full amount could be spent elsewhere,” it said in a statement.

“Given the high level of public interest in the European Union referendum debate, it is vital that official statistics are used accurately, with important caveats and limitations explained.”

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The side of the Leave battle bus contains the following sentences in large letters: “We send the EU £350 million a week. Let’s fund our NHS instead”. During a visit to a business in Staffordshire earlier this month Mr Johnson burned a symbolic £350m cheque in a publicity stunt.

This was despite the Tory MP and former London Mayor conceding in an ITV interview on 11 May that “Yes we do get some of it back” and that “if you take out the abatement and the money that comes back via Brussels the figure is obviously lower”.

But in that interview Mr Johnson still refused to admit the £350 million figure was misleading, despite the clear ruling from the UK Statistics Authority. “We think it’s relevant to keep people focused on the global figure, because that is the figure over which we have no control,” he said.

The Institute for Fiscal Studies earlier this week labelled the £350m figure "clearly absurd" and said that an accurate figure of the net UK contribution taking into account the rebate and spending in Britain was £175m a week - half the Leave figure.