An investigation into how a paedophile doctor at Addenbrooke’s Hospital was able to abuse his young patients has found clues were missed and that he manipulated rules to avoid detection.

Myles Bradbury was jailed for 16 years in December after being convicted of 25 offences including voyeurism, sexual assault and the possession of more than 16,000 indecent images in the period 2009-2013.

The report by Verita, a consultancy specialising in public sector investigations, found that the paediatric haematologist, who had worked at the hospital for five years, manipulated the system to perform “criminal, intimate examinations” on his patients.

The 42-year-old from Suffolk had taken advantage of the hospital’s appointments system and chaperone policy to commit his crimes on 18 patients.

Bradbury also used a “spy pen” to take photographs of his victims during consultations.

All of Bradbury’s victims, some of whom have since died, were suffering from haemophilia, leukaemia or other serious conditions.

The report, which was commissioned by the hospital, found that clues to his offending had been missed by colleagues, including phoning families on his personal number to make appointments and seeing some children more than necessary without recording the consultations.

Other missed warning signs included one nurse thinking Bradbury was “bending over backwards” to see his patients out of hours.

The report also notes his use of “excessive” puberty checks to assault his patients.

Bradbury was also able to befriend patients, grooming his victims by taking an interest in their outside lives. He also relied on the fact the department was busy to hide his crimes.

When colleagues did query his behaviour, the report notes how they were always given a “plausible” and acceptable excuse. Staff could not therefore be blamed for failing to raise the alarm over his behaviour, it notes.

However, Cambridge University Hospitals NHS Foundation Trust was praised in the report for acting decisively after concerns were raised in November 2013.

A woman complained after her 11-year-old grandson was asked to strip naked and touch his genitals. After she informed the paediatric day centre, Bradbury was suspended, and only returned to the hospital for formal interviews.

Bradbury was described by the trial judge as one of the worst paedophiles he had ever encountered.