In a secure mental unit, Huntley is charged on two counts of murder

Fiancée Maxine Carr is charged with attempting to pervert the course of justice

Ian Huntley was charged yesterday with murdering Holly Wells and Jessica Chapman by police investigating the Soham double killing.

Seventeen days after the 10-year-olds disappeared, Mr Huntley, a secondary school caretaker in the Cambridgeshire town, was taken to a mental health unit. He had been the subject of a late-night meeting between doctors and police, who knew he would have to be charged or released at 6am today. In the early hours of yesterday, Mr Huntley, aged 28, was detained at Rampton high-security hospital in Nottinghamshire, having been sectioned under the 1983 Mental Health Act.

After an urgent meeting with the Crown Prosecution Service, two detectives from Operation Fincham visited the unit and charged him with two counts of murder at about 5pm.

His fiancée, Maxine Carr, was charged last night with attempting to pervert the course of justice. Ms Carr, 25, is a former teaching assistant at the primary school the girls attended. She will appear at Peterborough magistrates' court this morning.

Extra police were drafted into the centre of the city last night to surround the court building, because of concern that members of the public might mount violent demonstrations against anyone accused of involvement in the double killing.

During the day, expressions of grief and anger and messages of sympathy for the girls' parents filled websites and books of condolence across the country. Floral tributes continued to flow into Soham, carpeting the cemetery of St Andrew's Church.

Shortly after 6pm, Detective Chief Inspector Andy Hebb said: "I can tell you that, in the last hour, detectives from this force have driven to the secure unit and have charged Ian Huntley with two counts of murder.'' The caretaker was due to appear before magistrates in Peterborough this morning but police later said that, after a further assessment in Rampton, his case would not be listed until "he is deemed fit to attend".

Mr Huntley and Ms Carr were taken to separate police stations to give witness statements on Friday night and arrested in the early hours of Saturday morning. They were brought before magistrates at hearings when detectives applied for two extensions to hold them until this morning.

Psychiatrists from Rampton gave Mr Huntley two medical examinations and decided he could no longer be held in police custody. He can now be held for assessment for up to 28 days under Section 2 of the Mental Health Act. But doctors could keep him there for a further six months if a Section 3 order, for treatment, is sought.

Cambridgeshire's Deputy Chief Constable, Keith Hoddy, said police were as certain as they could be that the dead girls discovered among trees beside a remote track near Lakenheath air base in Suffolk on Saturday were Holly and Jessica. But he added that a final positive identification might take weeks. The girls were last seen in Soham at 7.20pm on 4 August and there were a number of false leads before the arrests were made.The distress to their waiting families was made worse by a number of false leads. But the discovery near Lakenheath on Saturday dealt the final blow, extinguishing all hope of their safe return.

Yesterday, officers continued to search the home of Mr Huntley and Ms Carr and the grounds of Soham Village College, the town's secondary school, where a find of "major interest'' had led to their arrest. Officers also examined St Andrew's Primary School next door – where Ms Carr had taught the two girls until last month – as well as the home of Mr Huntley's father in Littleport, about 10 miles away.

Forensic science officers were still examining the site near Lakenheath, from where the victims were taken to Addenbrooke's Hospital, Cambridge, for further post-mortem tests.

Yesterday, the residents of Soham continued to grieve for the two schoolfriends, doing what they could to come to terms with their rage and disbelief.

The disappearance of Holly and Jessica has proved one of the most harrowing cases of its kind in recent years and has shocked people across the world. By late yesterday, 31,000 people had written messages of condolence on websites set up by Cambridgeshire police and the county council. Books of condolence, locally and in towns across the country, were filled with expressions of desolation.

One woman wrote: "I, and the rest of the world, cannot comprehend why these little ladies were on the brink of life here on earth before it was snatched away from them, but in heaven they will laugh and play and shine for ever.''