Friday's tribute to the best friends, at Ely Cathedral in Cambridgeshire, will be attended by about 2,000 people and will include hymns, poems and readings chosen by their families.

Holly and Jessica's school friends, teachers and many of the police who searched for them are expected to be among the congregation at the invitation-only service.

Reverend John Inge, Vice-Dean of Ely cathedral, told BBC News Online the girls' families wanted the service to be positive.

We are trying to emphasise all that's positive and good that has come out of this, as well as the hurt and loss

Reverend Tim Alban Jones

"As well as celebrating the lives of Holly and Jessica they want to give thanks to the people of Soham, who have helped them through these terrible times," he said.

The 10-year-olds' bodies were discovered in Suffolk on 17 August, almost two weeks after they went missing, and have now been released so that funerals can be held.

'In our thoughts'

Soham vicar, Reverend Tim Alban Jones said the service would be "a celebration and not a memorial".

"We are trying to emphasise all that's positive and good that has come out of this, as well as the hurt and loss," he added.

Mr Inge said: "I think they want to celebrate the good things about the lives of these two girls and all the good that came into the world through them."

Up to 2000 people are expected to attend the service

Ely Cathedral was requested by the girls' families because the local church in Soham could not accommodate the number of people attending.

Mr Inge said the cathedral community had been pleased to help organise the event for the families, who had been "very much in our thoughts".

He said coach companies had offered to transport people to the service and a local printers was preparing the programme for no charge.

"Our energy has been put into what will be one of the largest services in living memory," Mr Inge added.

Funerals

Police have asked anybody without a ticket for the service, which starts at 1700 BST, to stay at home and watch it on television.

Because of fears that huge numbers of people could turn out to pay their respects they have decided not to broadcast any sound or pictures outside the cathedral.

Mr Inge said: "I think anyone was been around here, and indeed has been to Soham, will know the immense feeling that this particular event has generated.

"And I think that any hint that it would be public would mean the place would be swamped."

Private funeral arrangements for the girls are now being made.

Holly is to be buried and Jessica will be cremated in separate ceremonies, which could be as early as next week.