The breast cancer screening error may have affected thousands more women across England, one researcher at Kings College London has claimed.

Jeremy Hunt told MPs in May that a “computer algorithm failure”, which dated back to 2009, meant a group of women were not sent routine screening invitations before the cut off point of their 71st birthday.

Hunt said initial estimate by Public Health England (PHE) predict that up to 450,000 women may have been affected by the glitch, which dates back to 2009.

However Professor Peter Sasieni, a cancer screening and prevention researcher at King’s College London, has claimed the error could date back to early as 2005.

In a letter published in the Lancet medical journal, Sasieni said he had studied data from the screening programme between 2004 and 2017, which included looking at the number of eligible women who were sent invitations each year from the ages of 45 to 70.

He claimed that a further 140,000 women may have been affected between 2005 and 2008, making the total more than 502,000.

Sasueni said: “Data that might have alerted people to the lower than expected number of invitations being sent to women aged 70 were publicly available, but no one looked at them carefully enough. Some of the fault lies in the way the data were presented, but it is also unclear whose responsibility it is to monitor such outcomes.”

Professor John Newton, director of health improvement at PHE, told the BBC the analysis was “flawed” and said PHE’s top priority was offering support to those women who had been affected by the error.

Baroness Delyth Morgan, Breast Cancer Now CEO, said the claims were “concerning”.

She added: “We urge Public Health England to make clear the full extent of the error as soon as possible.”