Labour is set to accuse the Government of “insulting the intelligence of hard-working families” with another attack on the Conservatives’ economic record.

In a campaign visit to Blackpool on Friday, shadow chancellor Rachel Reeves will unveil her party’s latest attack advert, focusing on a “tax double whammy” that Labour says will leave families £870 worse off.

Speaking ahead of her visit, Ms Reeves said: “Every time Rishi Sunak goes on the television claiming he is cutting taxes, he is insulting the intelligence of hard-working families.

“Under the Tory tax double whammy, for every extra £10 people are set to pay in higher tax they are only going to get £5 back, and the average household will still be £870 worse off.

“Working people can see through the Tories’ tax con. It’s giving with one hand and taking with another.”

The figures are based on forecasts from the Office for Budget Responsibility which show tax rises from frozen personal allowances will amount to £41.1 billion by the end of the decade, while tax cuts over the same period total just £21.4 billion.

Ms Reeves added: “After 14 years of working people footing the bill for Tory chaos, it’s time for change.

“Rishi Sunak should end the chaos, call an election and give the public the chance to vote for a changed Labour Party that will change Britain for the better.”

Treasury minister Bim Afolami said: “Because of the progress we have made, the economy is turning a corner. This has meant Rishi Sunak and the Conservatives have been able to afford tax cuts – putting £900 back in the pockets of the average worker.

“As part of this plan, we have committed to phase out national insurance altogether. We’ll do so over the long term, when it is economically responsible to do so, ending the unfair double tax on work.

“This will result in a simpler tax system which rewards and incentivises hard work.

“Despite all their talk Labour have no plan to cut the burden of tax. Instead, their plans for unfunded spending and their 2030 decarbonisation promise would mean thousands in extra tax for working families taking them back to square one.”

Ms Reeves’ visit comes less than a month before voters go to the polls in a parliamentary by-election in Blackpool South following the resignation of former Conservative MP Scott Benton.

Mr Benton quit Parliament after he was caught in a lobbying sting and found to have breached Commons rules.

With a Conservative majority of just 3,690, Labour is optimistic about its prospects of securing another by-election victory, its eighth gain since 2019.

Voters across England and Wales will also take part in local elections on the same day, May 2.