The Sarah Payne murder inquiry is now the most expensive since the IRA bombing of the Grand Hotel in Brighton in 1984.

Sussex Police today said more than £1,250,000 had been spent so far on the hunt for Sarah's killer.

A force spokesman said: "It is certainly one of the largest amounts ever spent on one inquiry, and probably the biggest since the Grand Hotel murders.

"Having said that, the money is not a prime consideration. We will use whatever resources are necessary to bring Sarah's killer to justice."

Most of the cash spent so far is "new" money. Leaving aside officers' wages that would have been spent anyway, about £800,000 has been spent on officers' overtime, hiring search equipment and materials, and extra use of the force helicopter.

The extra cash will come from the force's operational resource budget and there are no plans to apply to the Home Office for financial aid.

Eight-year-old Sarah Payne was kidnapped from a field near her grandparents' home at Kingston Gorse, East Preston, on July 1.

Her naked body was found in a shallow grave off the A29 near Pulborough. She had been sexually assaulted and either strangled or suffocated.

A 41-year-old man from Littlehampton was arrested and later released.

The inquiry, now four months old, continues and there are still 60 detectives working on the case, led by Detective Superintendent Peter Kennett.

Police are tight-lipped about developments but it is known they are awaiting the results of scientific tests on dozens of samples.

Yesterday Sarah's parents took their campaign to give parents greater access to information about sex offenders living in the community to the Conservative Party conference in Bournemouth.

Her mother Sara told a meeting their campaign had attracted mass public support.

Mrs Payne said parents had a right to information which would allow them to protect their children.

She added: "We have trusted the Government for long enough. Now we need to start trusting ourselves."