An ally of Andy Burnham tipped for a Cabinet role has admitted using AI to help make the case for tax-and-spend reforms.

Louise Haigh, who ran Mr Burnham’s Makerfield campaign, wrote an article calling for an increase in capital gains tax and a relaxation of the fiscal rules to allow the Government to borrow billions more.

She was accused of using AI to help write the 2,500-word piece published in Renewal, the Left-wing magazine.

Archie Hall, a journalist at the Economist, used an AI detection tool to examine the article.

The tool, called Pangram, concluded with “high confidence” that only 6 per cent of the article was written by Ms Haigh.

Another 57 per cent was directly written using AI and a further 37 per cent was AI-assisted, meaning some sentences had the tone adjusted or restructured using intelligence software.

Posting on X, Mr Hall said: “The document is almost certainly largely AI-written.

‘Focus on the ideas, not the editing’

A spokesman for Ms Haigh said: “The words and ideas are Louise Haigh’s – to suggest otherwise is untrue. Like most articles, this was written following a series of conversations and AI editing tools were used for version control. 

“We hope people focus on the transformative ideas contained within it and not the editing process.”

In the article, published in print on Saturday but released online last month, Ms Haigh appeared to use the same phrase twice, suggesting that a command to replace one sentence with another had accidentally been left in the final version.

The article said: “So, whether it’s the council tax bill, income, corporation or inheritance tax, we need to make sure that our tax system, across the board, is fair, incentivises work and encourages’ with ‘is fair, incentivises work, and encourages productive economic growth.”

Robert Jenrick, the economic spokesman for Reform UK, said: “First we had Rachel Reeves plagiarise parts of her book, and now we have Louise Haigh using ChatGPT to pull together Andy Burnham’s policy. 

“It’s farcical. If Labour wants to raise taxes even higher they should call a general election and see what the British people think.”