Boris Johnson has been spared a potentially embarrassing spotlight on the state of the public finances after the official fiscal watchdog was blocked from releasing new figures on the state deficit and debt.

Cabinet secretary Sir Mark Sedwill barred the Office for Budget Responsibility from publishing its revised public finance forecast on Thursday, ruling it would breach civil service “purdah” rules in the election period.

Chancellor Sajid Javid has come under attack for refusing to release the normal autumn forecasts for the economy after cancelling the Budget announced for 6 November.

OBR chairman Robert Chote last week told MPs that the watchdog would nonetheless go ahead with releasing the figures, given the importance of the economy to the looming general election debate.

He told a House of Commons committee that publication would not contravene the restrictions placed on the OBR, adding: “We therefore intend to do so on 7 November.”

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The update was thought unlikely to make happy reading for the government, with the economy stumbling because of the Brexit crisis and borrowing rising sharply.

One think-tank has predicted the deficit target will be overshot by £16 billion this year, because of the slowdown and big spending pledges made by Mr Javid.

However, the OBR said today that it was in fact planning only a “technical” adjustment to its earlier analysis, rather than new forecasts on the impact of Brexit or the future path of the public finances.

The new report would have incorporated changes to the treatment of government liabilities, such as student loans, which one think-tank has calculated will add a further £19 billion to the deficit.

In a statement, the OBR said: “As we notified the Treasury and Treasury Select Committee on 29 October, we had planned to publish a technical restatement of our March public finance forecast this morning, bringing it into line with current ONS statistical treatment – for example, the new treatment of student loans implemented in September – but not incorporating any new forecast judgements regarding the economy, the public finances or the impact of Brexit.

“This will no longer go ahead as the Cabinet Secretary has concluded that this would not be consistent with the Cabinet Office’s General Election Guidance.”