A Labour frontbencher has been told she should repay more than £1,140 after an inquiry found she used prepaid Commons stationery to send out political material to voters in breach of House rules.

The Commons Standards Committee found that shadow health minister Rosena Allin-Khan sent out 1,624 copies of her “Brexit Update” letter on House of Commons headed notepaper in prepaid Commons envelopes in the run-up to last year’s general election.

Under the Commons rules, MPs can only use House stationery for their work as a Member of Parliament and are banned from using it for campaign material.

The Parliamentary Commissioner for Standards, Kathryn Stone, found that Dr Allin-Khan’s mailshot used “public resources to highlight to a group of voters her position and record on an issue that was one of the key themes of the imminent election”.

In her report to the committee, Ms Stone noted that it was the third time in three years that Dr Allin-Khan, the Labour MP for Tooting, had breached the rules.

They included a previous occasion when she sent out party-political literature on stationery with the royal badge of the crowned portcullis.

The committee recommended she should repay the £1,142.52 cost of the mailshot and should make a personal statement in the House apologising for the breach.

It said she should also agree steps to prevent further breaches and that her progress should be reviewed after three and six months.

“Given her previous breach and subsequent assurances, and the fact that the letter was sent at a period of heightened political sensitivity, we would expect Dr Allin-Khan to have reflected more carefully, or indeed sought advice, on the content of her mailing before sending it,” the committee said.

“We would regard any further breach of the Code of Conduct by Dr Allin-Khan which evidenced a lack of proper attention to the rules as a matter which might call for a more serious sanction.”

A spokesman for Dr Allin-Khan said: “Rosena apologises for breaching the rules. She fully accepts the committee’s recommendations and had already offered to reimburse the costs. We have taken steps to ensure this does not happen again.”