The NHS has spent £25.3million in compensation and legal fees over the past five years in cases where patients have left surgery with foreign objects inside them.
At least two people a week are affected, figures obtained by HuffPost UK show.
Some 668 successful cases have been settled by the NHS in England since 2013. Around £23.4m of the cash went towards damages and claimant costs.
Objects left inside patients can range from swabs and needles to “screw fragments and drill bits”, and have in the past included surgical implements and wires.
One such incident in 2012 saw a man leave hospital following an appendix operation with eight-inch long forceps left inside him. The grim discovery was only made weeks later during a routine X-ray, prompting an urgent investigation by the hospital involved.
NHS Improvement, which handles negligence claims within the health service, has described the issue as a “never event”, a term used to describe “serious incidents”.
But a patient safety charity said HuffPost UK’s figures, obtained by a freedom of information request, showed such incidents continue with regularity. Peter Walsh, of Action Against Medical Accidents, said: “Really and truly this should never happen – but it has been happening for many years.
“We all know healthcare is complex, and that things can go wrong, but this is one of the most straight forward things to avoid.
“When foreign objects go into someone’s body they should be counted on the way in and counted on the way out and double checked. It is so perfectly avoidable.”
Walsh said the figures are unlikely to show the true extent of the issue, as most patients the charity assists do not wish to claim compensation.
He added that many of those subject to botched procedures want to see systems and processes changed to prevent the issue from reoccurring.
A recent NHS report described how the problem persists amid the hectic environment of an operating theatre, with staffing levels and workloads also cited as contributory factors.
NHS director for patient safety, Aidan Fowler, said: “In the vast majority of cases patients receive safe care. Although events like these are thankfully rare, it is vital that when they happen hospitals investigate and take action to improve safety and reduce the risks of them happening again.”