Police have warned the public to stay away from a convict who is the latest to go on the run from an open prison.
Officers said that David Blood, who is serving a life sentence for robbery, may pose "a threat to the public".
The 48-year-old absconded from Ford Prison in West Sussex, some time between 8.30am and 1pm on Thursday.
It is thought to be the second time he has escaped from an open prison. It is understood he went missing from HMP Sudbury in Derbyshire in April 2012.
On that occasion, he was not found until almost three months later.
Blood was jailed for life at Stafford Crown Court in 2003 after he was convicted of robbing a post office in Sutton Coldfield in the West Midlands with a number of other men in December 2000.
PC Stephen Reed said: "Because of Blood's record, we have to consider that he could pose a threat to the public.
"I would urge anyone that sees him to contact us on 999 rather than approaching him."
Police have described Blood as 6ft 1in tall (1.85m), of small build with brown eyes and cropped black hair. He is known to have links in Staffordshire and Warwickshire.
Blood's escape is the latest in a spate of inmates absconding from open prisons.
The most high-profile offender to go missing was the violent armed robber Michael Wheatley- known as Skullcracker.
Wheatly carried out a raid on a building society while on the run after being let out of the Standford Hill prison in Kent last month.
He was later jailed for life.
A Ministry of Justice spokesman said: "The Justice Secretary has been clear that keeping the public safe is our priority and has already ordered major changes to tighten up temporary release processes and open prison eligibility.
"Absconds have reached record lows under this Government - down 80% over the last 10 years - but each and every incident is taken seriously, with the police contacted as a matter of urgency.
"Open prisons and temporary licence are an important tool in rehabilitating long term offenders but not at the expense of public safety."