Police hunting missing schoolgirl Sarah Payne have arrested a registered sex offender over her disappearance.

Officers seized the man in his 30s from his home in Wirral, Merseyside, early on Wednesday.

The arrest, described by police as 'routine', came as part of a nationwide search for the eight-year-old, who disappeared on Saturday, July 1.

However, police said they were simply hoping to eliminate the man from their inquiries and said they expected him to be released soon.

The man was the third to be arrested in connection with the suspected abduction. Two others were released on police bail last week.

The arrest came as police received more than 1,500 calls in just two hours following reports of a possible sighting in Scotland.

A youngster who is said to have fitted Sarah's description was seen at a Shell garage off the A80 at Cumbernauld, near Glasgow, at about 6am on Monday.

She was believed to have been with a man matching the e-fit picture released by police yesterday following a 'sighting' at an M6 service station more than a week ago.

However, police warned that they didn't believe the girl in Scotland was Sarah.

Sussex Police Assistant Chief Constable Nigel Yeo said: "We have had information about a possible sighting in Scotland.

"But the officer in Scotland who we have been liaising with thinks that it is not Sarah and that it is not the person from the M6."

The first reported sighting of the suspect man was at Knutsford Services on the M6 in Cheshire at 5am on Sunday, July 2 - just 10 hours after Sarah vanished.

Police scrambled a helicopter yesterday amid reports Sarah had been spotted with a man in South Wales.

The aircraft patrolled over Pontypridd, Mid Glamorgan, for an hour after an unconfirmed sighting of the eight-year-old with a man outside a pub but flew back to base after scouring the area in vain.

Reward money totalling more than £130,000 has now been put up in a bid to move the hunt further forward.

Anti-crime hotline scheme Crimestoppers has pledged £80,000 and today The Sun newspaper offered another £50,000 to nail the man believed to have abducted Sarah.

Described as white and in his 30s, the unshaven man is thought to be 6ft tall, with crinkly, sandy hair and of solid build.

He was wearing washed-out black jeans and a dark grey bomber jacket with plum shirt when spotted in Cheshire.

A witness, who said the girl with him looked 'upset' and was wearing a blue dress like Sarah's, also said he had a wide nose and strong jawline.

Sarah's distraught parents today made a fresh appeal for the person feared to be holding Sarah to come forward. Sara and Michael Payne, both 31, urged the e-fit suspect to get in touch with police.

Speaking on Sky News, Sara said: 'We really need you to come forward. We need to get on with this. We want to find our daughter so please come forward.'

Michael added that the family were refusing to give up hope. 'If any of us start going down a dark alley then someone brings us back,' he said.

Showing off thousands of letters sent by well-wishers, he added: 'This is what keeps us going.'

He and Sara spoke as Steps, Sarah's favourite pop group, took time out from recording their new album to put together a special message for the missing youngster.

They told Sarah 'that the whole nation is thinking about you' and said they were looking forward to meeting her when she returned home.

Band member Lee said: 'Sarah - everybody wants you to come home safe and well.'

Claire said: 'If anyone out there knows anything or has seen anything, no matter how small, please contact the police.'

And Faye added: 'Where ever you are we're all thinking of you and look forward to seeing you.'

Police received 800 calls in just 24 hours after details of the initial Knutsford 'sighting' were released.

Callers from all over Britain rang the incident room, while people also got in touch from as far away as Israel, Germany, Spain and Greece with reports of possible sightings.

Some 6,000 people have now rung in - more than 10 times the response of a good response from a Crimewatch TV appeal.

But police are still hoping they will get the breakthrough they need in tracking down the e-fit suspect. Assistant Chief Constable Nigel Yeo, from Sussex Police, said: 'We really need to get hold of him.

'We want him to come forward to eliminate him, or otherwise, from this inquiry. Until we have a reason to stop going into it we will continue to look at it.'

Police are also still hunting the drivers of silver-grey Mondeo-style car and a white Transit van spotted around the time Sarah disappeared.

They believe she could have been abducted and driven away in the van and appealed for people in the local area to call if they had seen a white van being worked on or if there was one near a lock-up or garage.

Officers were also searching for a cyclist and some walkers believed to have been in the area at the time. Blonde Sarah disappeared a few hundred yards from her grandparents' house in East Preston, near Ferring, West Sussex, after a row with her brothers and sister as they played together in fields.

Wearing a dark blue Fred Perry tennis-style dress and black shiny shoes with Velcro fastenings, she was last seen walking across the fields towards the house in Peake Lane soon after 7pm on Saturday, July 1.

Anyone with any information should contact the Sussex Police hotline on 0845 60 70 999, Crimestoppers on 0800 555 111 or the National Missing Persons Helpline on 0500 700 700.