2 Flee London Prison in Copter

LONDON — A helicopter landed in the exercise yard of top-security Gartree Prison today and whisked a murderer and another prisoner to freedom, police said.

Guards tried to prevent the two men from running to the chopper but other prisoners mobbed the guards and the helicopter lifted off about 30 seconds after it landed. Police said the chopper then landed several miles away and the two men hijacked a succession of cars in making their getaway. It was the first helicopter escape from a prison in Britain, although similar breakouts have been staged elsewhere.