The death of a nine-year-old boy during a routine operation on his finger was caused in part by "neglect", an inquest jury found yesterday.

Tony Clowes was starved of oxygen because doctors did not spot that a tube leading to an anaesthetic machine was blocked. The boy, from Dagenham, Essex, had been admitted to Broomfield Hospital in Chelmsford in July 2001 after the tip of his finger was sliced off in a bicycle accident.

The oxygen tube, which should have been used only once, had been kept in a drawer, where it became blocked by a cap from another piece of equipment. Tony suffocated in the pre-operative room. A post-mortem examination found that he had suffered irreversible brain damage because of a lack of oxygen.

An inquest jury at Chelmsford coroners' court returned a verdict of "accident contributed to by system neglect". Despite strict guidelines from the Medical Devices Agency - that breathing equipment should be destroyed after an operation - Bruce Emerson, a consultant anaesthetist from the hospital, admitted it was "common practice" for tubes to be washed and used for up to two weeks. He said he was "not aware" of the guidelines.

Dr Emerson said he only became aware there was a problem with Tony's treatment when an alarm went off.

"We were truly all devastated. On behalf of the staff, we would like to offer our deepest, deepest apologies," he said.

Essex Police launched an investigation into 13 other cases of blocked anaesthetic tubes before discounting foul play.

At the inquest, Tony's father, George, spoke of his distress when doctors asked him to follow them into a side room where they explained there had been a problem with the anaesthetic and that Tony had died. He was told a "disaster" had occurred minutes after he had kissed his "lively, healthy" son goodbye and said he would see him in a couple of hours.