A former teacher has been given a 25-year sentence for a campaign of abuse involving a string of sex offences against young boys.

Dr Tyrone Murray Castles, 59, was described by a judge as someone who had been concealing a lie, presenting himself as a respected teacher but hiding that he was a "monster".

Castles, of Dockray, Penrith in Cumbria, admitted a number of indecent assault on boys under 14 years of age and two serious sexual offences on one boy and appeared in the dock at Norwich Crown Court for sentence on Friday.

The offences are said to have taken place in the late 1980s and early 1990s, while Castles taught at Glebe House School, in Hunstanton, and involve a total of five victims.

Norwich Evening News: Former teacher Tyrone Castles, who has appeared in court charged with a string of sex offences against boysFormer teacher Tyrone Castles, who has appeared in court charged with a string of sex offences against boys (Image: Chris Bishop)

Castles later went on to be head of Earlham High School, Norwich, but none of the charges relate to his tenure there.

Philip Farr, prosecuting, said Castles put a lot of planning into the abuse and said Castle's actions were a campaign of abuse against vulnerable children.

One victim described Castles as a Pied Piper character who was popular with pupils and told how he felt trapped and isolated by the abuse and felt he had no one to turn to.

In an impact statement one victim said the abuse had been like having a black cloud over him.

Sentencing him, Judge Andrew Shaw handed Castles a 25-year term with 24 years custody and one year extra on licence.

He told Castles: "Anyone looking at a history of your life would conclude that from the ages of 30 until your late 50s you were a virtuous family man, a hard working man, someone to whom others looked up to. The reality is that for nearly all your married life you have been concealing a lie. You have been concealing a monster."

Castles, who showed no emotion as he was sentenced, was also placed on the sex offender's register for life and made subject to a sexual harm prevention order.

David Wales, defending, said Castles was full of remorse.

He said: "He is aware of the harm that has been caused to his victims. He is aware of the damage he has done. He is going to carry that knowledge with him to his grave."