Osborne told to stop the spin and open up official statistics to all

George Osborne has abandoned a pre-election pledge to change rules that give ministers and advisers a day to view key data before its release (PA)

The Chancellor has been accused of undermining public trust in government statistics by refusing to change rules that allow ministers and their advisers to see key economic data a day before its general release.

In a strongly worded letter to George Osborne, Sir Michael Scholar, the chairman of the UK Statistics Authority, said the practice was out of step with other countries, increased voters' fears that official figures were subject to spin and opened the door to leaks – accidental and intentional.

"The Statistics Authority believes that the current arrangements for pre-release access are highly damaging to public trust in official statistics," he told Mr Osborne.

"Pre-release access encourages the belief – held by five out of six people in recent polls – that ministers and their advisers manipulate official statistics. It increases the likelihood of unauthorised disclosure and dishonesty.

"It is inconsistent with best international practice, the UN and EU Codes on Statistics, with the recommendations of the Treasury Select Committee, and with your own party's stated policy before the last general election."

Mr Osborne confirmed in a letter to MPs that the Government had abandoned a pre-election pledge to reduce the advantage that ministers enjoyed in accessing official statistics.

He was responding to a "serious lapse" in security in which highly market-sensitive inflation figures were released 17 hours early to hundreds of unauthorised officials. Operations had been updated to ensure there was no repeat of the "unfortunate incident", the Chancellor said, but there had been no change of heart over pre-release.

The public, he said, "expected a response [from the Government] at the time of release". In other words, ministers and advisers needed time to analyse the figures and decide what to say before releasing them.

But Sir Michael said he did not agree with the Chancellor's position. "I do not accept the argument in your letter that, because the public expect ministers to be briefed at the time statistics are published, 24 hours' notice is needed, as the present rules allow. That expectation could, and should, be changed in the interests of improving trust in official statistics. It has already been changed in a number of countries, including the US, which operate to much tighter rules than you are defending."

He said it would obviously be "inconvenient for special advisers and others to lose the 24-hour period in which they can develop a line to take on forthcoming statistics. One of your colleagues told me that the advice of special advisers on this point had been influential [when ministers were discussing] my request, to which you refer: I found that disappointing, but unsurprising."

He urged the Government to reverse its opposition to reform. Sir Michael was due to retire in July but agreed to stay in his post after the Government's candidate to replace him pulled out.