Volunteers and friends scour wood for missing nightclub woman, 22

Details of the offer came as hundreds of volunteers joined the search of woodland for the woman who has not been seen since the early hours of Saturday after leaving the Suju nightclub in Swindon.

Police issued a new poster, with details of the reward, which is being pinned up across Wiltshire and also warned people to be extra careful and not to be out walking alone.

The poster includes a photograph of Miss O’Callaghan and CCTV footage of her leaving Suju at 2.50am. It also features a picture of her mobile phone, an LG E900 Optimus 7, which was on in the 4,500- acre Savernake Forest area, near Marlborough, at 3.24am.

About 400 people queued up to be split into teams to join the specialist police officers combing the thick undergrowth of Savernake Forest for clues to her disappearance.

Also assisting in the search were police dogs and members of the Wiltshire Search and Rescue team. Police had also drafted in other specialist search and rescue experts to help.

Miss O’Callaghan’s boyfriend Kevin Reape, 25, is also believed to have joined the searches, which continued until dusk.

Miss O’Callaghan has not been seen since she left the Old Town area to walk the half-mile home to the flat she shared with her boyfriend.

Detective Superintendent Steve Fulcher, who is leading the inquiry, said: “There were a number of vehicles moving through the High Street between 2.55am to 3am.

“We would like to identify the people in those vehicles as possible witnesses.

“I’d like to hear from anyone who saw any vehicles in or near beauty spots between Swindon and Savernake between 3am and 4am.

“I’d also like to... remind people to think about their personal safety.”