The trial of a former deputy head and three teachers at a former Suffolk school accused of a “regime of abusive behaviour” dramatically ended today after two of the defendants entered guilty pleas to four of the charges.

The remaining 20 charges were dropped.

Gerald West, the former deputy head at the Oakwood School in Stowmarket, had denied ten charges of cruelty to a child under 16 but today changed his plea to guilty on two of the charges and the jury at Ipswich Crown Court was directed to return not guilty verdicts on the remaining charges.

Michael Watts, a former child care officer at the school, had denied seven charges of child cruelty but today changed his plea to guilty on two of the charges. The jury was directed by trial judge Rupert Overbury to return not guilty verdicts on the remaining five charges.

Following the guilty pleas by West, 70, of Martins Meadows, Gislingham and Watts, 59, of Southampton, prosecutor Jacqueline Carey offered no further evidence against Stephen Player and Graham Hallett, who were both former senior masters at the school.

Player, 59, of London, had denied six offences of child cruelty and Hallett, 66, of Lancaster, had denied one offence.

West, who is known by his middle name Roger, and Watts will be sentenced on Friday.

Eric De Smith, 76, of Danes Close, Stowmarket, the former head of Oakwood was convicted at an earlier trial of four offences of indecent assault and three offences of indecency with a child and he will be sentenced separately on Friday

Explaining her reasons for offering no further evidence following the guilty pleas by West and Watts in the sixth week of the trial, Miss Carey said the prosecution was under a duty to review the state of the evidence as it came out in court.

She said that during the investigation into the allegations the complainants had made statements to the police and civil lawyers and had given evidence in court which in some cases had been different.

“Sometimes there have been differences In all three parts with some of these differences more significant than others,” said Miss Carey.

She said in the light of the guilty pleas by West and Watts the prosecution had decided not to proceed further against Player and Hallett and to offer no further evidence on the remaining charges for West and Watts.

During the trial the court heard that pupils at the school, who were described as “vulnerable” as they had been sent to the school because they had educational and behavioural problems, were allegedly subjected to physical ill treatment including slaps to the face, punches and kicks.

Several boys complained of being force fed if they didn’t finish their meals.

“The violence meted out to them was all too prevalent a feature of life at Oakwood school where a regime of abusive behaviour existed,” alleged Miss Carey.

Miss Carey said that when the defendants were interviewed about the allegations they denied being physically violent to pupils and said the alleged victims could be motivated by the hope of compensation arising out of a civil action.

She said that in the 1970s and some of the 1980s schools were allowed to physically discipline children by using “reasonable chastisement” which would usually be a smack to the back of the hand, the back of the legs or bottom or the use of a slipper or cane.

She said the use of physical discipline was banned by Parliament in 1987.

The offences were alleged to have occurred between 1974 and 1999 and related to 20 alleged victims.

Oakwood School opened in 1974 and shut in 2000.