SIAN O’ Callaghan was last seen leaving Suju nightclub in Swindon in the early hours of Saturday.

She is 22 years old and friends, family and acquaintances say there is no way she would disappear without a trace... but that’s what has happened.

This weekend, 60 police officers and at least 30 volunteers were searching for her.

Sian was last seen at 2.50am on Saturday.

Neither her parents nor her boyfriend have been able to get in touch with her since.

Police have been scouring Savernake Forest, near Marlborough, where her mobile phone is believed to have last been used.

Officers have also been out in force in Old Town, Swindon, in a bid establish her movements before she disappeared.

Friends of Sian have been so concerned they have put up posters appealing for information about her whereabouts.

Chief Insp Mike Jones, of Wiltshire Police, said yesterday: “For her not to return home after a night out or not contact family or her boyfriend is totally out of character, something she’s not done in the past, and this gives us extreme cause for concern.

“At the moment, we’re liaising with the immediate family, getting background information about her movements and general lifestyle.”

He said there was no obvious reason in her personal life for her to go missing.

He said: “We’re in Savernake exploring some areas but we are concentrating on other areas too.

“We are deeply concerned. All our efforts are directed at finding her safe and well.

“The reason for our concern is straightforward – it’s out of character. Time is getting on and we’ve still not had contact.”

Sian had been out with a couple of female friends on Friday night.

CCTV footage shows her leaving Suju at about 2.50am on Saturday, and turning left in the direction of Wood Street.

Earlier on, she had visited Long’s Bar in Victoria Road.

Police are asking any businesses in the area with CCTV cameras to come forward.

Sian is white, 5ft3in, and of medium build with brown hair and green eyes.

When last seen she was wearing a grey dress, a black bolero jacket, dark tights and flat boots. She was carrying a dark handbag which had a beige flower attached.

Sian is a regular Facebook user, but her account has not been used since Friday. More than 2,000 people have since accessed a Facebook group set up to find her.

If you have any information about her whereabouts, call Wiltshire Police on 0845 4087000 or Crimestoppers anonymously on 0800 555 111