Riot unit members have been called to a youth jail after a reported hostage situation between inmates.

Specially-trained officers were sent to Cookham Wood Young Offenders' Institution in Rochester this morning.

It is believed a 17-year-old detainee was threatened by a gang of other inmates in the exercise yard.

There are reports he was grabbed and a filed down sharp toothbrush 'blade' was held to his neck.

The Sir Evelyn Road-based facility, which houses 15 to 18-year-olds, has been on lock-down most of the day.

But it is believed officers from the Prison Service's Tornado team, stormed the yard and used fire-crackers to disperse the group and gain control.

One woman, who has a son inside the prison, but didn’t want to be named, said: “My son is only 16 and I am frightened for his safety, he called me from inside the prison to tell me about it.

“He said the teenager who was held at knifepoint usually stays in his cell and doesn’t mix with others, but was made to go an exercise on the yard.

“My son called back about an hour later and said riot officers had now gone in and had used fire-crackers and some sort of paint gun to get the situation under control.”

A Prison Service spokesman said: “Staff successfully resolved an incident involving a small number of offenders .

"No-one was injured and there was no threat to the public.”

A police spokesman said: “Our attendance has not been necessary.”

Cookham Wood was built in the 1970s, originally for young men, but its use was

changed to meet the growing need for secure female accommodation later on.

In 2007/8 it was converted into a juvenile centre and has the capacity to house 178 inmates.