A robotic computer programme removed hundreds of patients from a hospital trust's waiting list earlier this year, it has been revealed.

The error, which this paper reported in May, saw 1,800 patients deleted from Barking, Havering and Redbridge University Hospital NHS Trust's (BHRUT) waiting list.

Matthew Trainer, chief executive of the trust - which runs King George Hospital in Goodmayes and Queen’s Hospital in Romford - apologised to the affected patients, who had been waiting more than six months to be seen.

The 1,800 patients were removed from the waiting list without their GP being informed or BHRUT even being aware.

According to internal reports obtained via a Freedom of Information request, the error occurred because of the robotic process automation (RPA) programme that transfers patients between national NHS waiting lists and local hospital lists.

An “automated process” deleted patients from the waiting list after 180 days if the trust did not have enough capacity to offer them appointments within that time.

Minutes of a working group formed when the error was discovered in May show that at the time there was no “head of RPA” in charge of monitoring the robot after the previous person “moved on to another role”.

A staff member, whose name has been redacted, said: “There has been a lack of leadership and of governance in the process. Prior to RPA being implemented, there was an RPA steering group, which no longer exists.

“There has been a robustness in the monitoring process which had slackened due to lack of resource in the past few months. RPA will reduce a lot of waste in the system but will require governance and a lot of resource going forwards.”

An unnamed member of staff advised the working group that “robotics only do what they are programmed to do” and the way information is “fed into” the system needs to be monitored.

Supplier of the robot, software company Blue Prism, also carried out a review of the failure and found a “caching issue to do with the capacity of the robots” that causes their “memory to get used up”, the minutes show.

Another problem cited was a failure to manage the “mismatch” between the robot and various NHS waiting lists, which had been updated without telling the robot.

One member of staff suggested that even the recent rebranding of BHRUT’s internal computer system from Medway to Careflow could have had a “major impact” on the robotic system.

A similar waiting list incident first occurred at BHRUT in April 2019, when more than 200 patients were also automatically removed after 180 days.

To solve this, an additional “robotic process” was created, overseen by one person, which moved deleted patients back onto the right list.

The minutes also show that NHS Digital has been aware of patients being automatically deleted from its national waiting list after 180 days since at least 2017 but has “no plans” to change this rule.

Mr Trainer said: “We’ve put measures in place since fixing this error to monitor our systems which use robotic process automation more closely, including additional staff oversight.

“Our teams are working hard to see patients who have faced delays, reducing those waiting more than two years from 218 to zero in just two months.”

According to NHS Shared Business Services (NHS SBS), which partners with NHS organisations to improve efficiency, RPAs can take on “repetitive, time-consuming, mundane tasks”.

NHS SBS says there are now more than 77 robots across the health service, half of which assist finance and accounting departments.

A spokesperson for NHS SBS said it does not have any link with the BHRUT incident, as many trusts have their own RPA projects directly with suppliers such as Blue Prism.

Blue Prism and NHS England have been approached for comment but have not responded at the time of publication.