Police are appealing for help in finding a teenager who was last seen leaving a nightclub in Windsor.

Marnie Clayton 18, from Bracknell, Berkshire, left Atik in William Street at around 2am on Sunday morning, Thames Valley Police said.

She did not return home and was reported missing by her family just before 3am.

Ms Clayton is described as white, approximately 5ft 2in to 5ft 4in and of slim build, with brown hair.

The teenager, who was wearing a grey dress when she was last seen, is also known to frequent Reading town centre.

Police released photographs of Ms Clayton, including one taken on the night she went missing.

Detective Chief Inspector Jon Groenen, of Thames Valley Police, said: “This is out of character for Marnie, and we are becoming increasingly concerned for her welfare.

“I would appeal to anybody who knows of Marnie’s whereabouts to please call us on 101, quoting reference number 43220021633.

“If you see her, please contact us on 999.

“I would also like to appeal directly to Marnie: if you see this appeal, please contact your family or the police to let us know you are safe and where you are.”

Police said on Monday that the investigation is “fast-moving” and urged people not to speculate.

The force tweeted: “We would like to thank you all for your concern and for sharing our appeal to help locate Marnie.

“Marnie is still missing at the current time, and we would ask you to contact us if you have any information that can assist the investigation.

“We’d like to reassure the community that this is a fast-moving inquiry, and we are thoroughly investigating the circumstances.

“Please avoid speculation into the circumstances, but share any information you feel may assist the investigation by calling TVP on 101.”

A force spokesman added: “At this stage, we are unable to comment on specific lines of inquiry, other than to say we have a number of active lines of inquiry which are being investigated as a priority.”

Posting on Facebook, Atik said: “We are really concerned about the disappearance of Marnie Clayton and we have been working with the police all weekend on their investigation, and will continue to do so.

“We join everyone in hoping she is found safe and well.

“If anyone has any information, please contact the police on 101, quoting reference 43220021633 and if you see her or think you’ve seen her, please contact 999.”

A spokesman for the nightclub confirmed that CCTV footage has been handed over to the police.