Dr Myles Bradbury, who worked at Addenbrooke's Hospital in Cambridge, has pleaded guilty to six counts of sexual assault and 13 counts of engaging in sexual activity with a child.

Wearing a dark suit and blue tie at Cambridge Crown Court, Bradbury also pleaded guilty to three counts of causing or inciting a child to engage in sexual activity, one count of voyeurism and two counts of making indecent images of a child.

Prosecutor John Farmer said the offences involved 18 victims and dated back to 2009.

Paediatric haematologist Bradbury was bailed and told he would have to sign the sex offenders register. He pleaded not guilty to one count of sexual activity with a child and one of sexual assault, which Judge Gareth Hawkesworth said would probably remain on file.

A sentencing date was not given but the judge said Bradbury could expect a "substantial" custodial sentence.

As he left court, Bradbury told reporters: "I'm so sorry."

He refused to answer further questions.