Daring escape foiled by jail staff who read between the lines

For free real time breaking news alerts sent straight to your inbox sign up to our breaking news emails Sign up to our free breaking news emails Sign up to our free breaking news emails SIGN UP I would like to be emailed about offers, events and updates from The Independent. Read our privacy policy When Brian Lawrence, a convicted murderer, wrote the words "more heat, less light" in one of his letters from the Isle of Wight's Parkhurst prison, he must have hoped warders monitoring his mail would put his reference down to his former career as a science teacher. Instead, the security team at the former high-security prison, which once housed some of Britain's most notorious killers, became suspicious that the 67-year-old inmate, who was convicted of murdering a friend of his former lover and hiring a hitman to kill two others, was using a tried and tested method to conceal invisible messages. Closer examination of the letters showed that, under the guise of routine correspondence, Lawrence had been using lemon juice as an invisible ink to convey details of a spectacular plot to escape the prison – once considered the British version of Alcatraz – using a helicopter. Investigators found that for several months Lawrence had been diligently drawing maps and using encrypted instructions, including codes hidden in sudoku puzzles, to convey to his accomplices his plan to bring a helicopter into one of the few parts of the prison grounds not protected by reinforced nets.