The UK’s statistics watchdog has opened an investigation into remarks made by Rishi Sunak about the economy “going gangbusters” amid concerns that politicians could misuse economic data in the run-up to the election.

Sir Robert Chote, chair of the UK Statistics Authority, will examine whether the prime minister repeated comments that were “taken out of context” and exaggerated the Conservative party’s economic record.

The phrase “going gangbusters” was used by an official at the Office for National Statistics (ONS) during a briefing about the economy with journalists before becoming the basis of a Daily Mail front page story last month. A week later Sunak, in an interview on the Radio 4 Today programme, repeated the term.

In May, official figures showed the UK was officially out of recession and that the economy grew by 0.6% in the first three months of the year after two quarters of declines in the second half of 2023.

Referring to figures showing the economy expanded in the first three months of the year, he told listeners: “The facts are the facts. You had, I think, the person from the Office for National Statistics talking about the economic growth that the country produced in the first quarter of the year. He said what he said about that and I think he used the term ‘gangbusters’, so I will leave it at that.”

Chote’s intervention came soon after he began a review of Sunak’s claim that independent civil servants calculated that Labour would raise taxes by £2,000 for everyone should it win the election on 4 July.

Labour has complained that the figure was wrong and was erroneously described as independently verified by Treasury civil servants.

On Tuesday, before the TV debate between Sunak and Labour leader Keir Starmer, Chote wrote to the main political parties and top civil servants to warn them about “ensuring the appropriate and transparent use of statistics”.

Chote previously ran the Office for Budget Responsibility (OBR), the Treasury’s independent forecaster, and was the head of the Institute for Fiscal Studies thinktank, a leading arbiter of government tax and spending policies

He is expected to take charge of the review into Sunak’s comments, which could result in a warning to Conservative central office to stop using the term “gangbusters” in election broadcasts and debates or in printed and online material.

A spokesperson for the ONS said: “We have clarified to any outlet or journalist that has approached us that [gangbusters] is not a word we would use to describe the UK economy.”

It is the regulator’s role, and not the ONS’s, to contact political parties about their use of data, said the spokesperson.

Complicating the outcome of the review will be that the source of the comment is the chief economist at the ONS, Grant Fitzner, who used the phrase “going gangbusters” in a briefing with journalists.

The Daily Mail quoted him as saying: “To paraphrase former Australian prime minister Paul Keating, you could say the economy is going gangbusters.”

The ONS has claimed that he was not describing his own view of the economy when he used the phrase and it was “taken out of context” when it became the basis for a story published by the MailOnline and the front page of the Daily Mail under the headline: “Economy’s going gangbusters – Not the verdict of a Tory, but the chief economist of the ONS as Britain outpaces US, France and Germany.”

Other newspapers, including the Sun and the Telegraph, used the phrase in later stories.

Chote may be forced to admonish Fitzner for straying into commentary about the economy that could be interpreted as biased.

Dario Perkins, a senior economist at the consultancy TS Lombard and former Treasury official, said it was unwise for the ONS to say the economy was growing quickly and wrong for the prime minister to use one quarter of GDP growth to argue that economic health had been restored.

“The ONS is not supposed to use these kinds of descriptive words to tell a story about the economy. And it is also wrong to say the economy is booming in the first three months of the year when we have only just recovered lost growth from last year’s recession and suffered the worst incomes squeeze in a generation.”