Watford police use stun gun on man with knife in John Lewis
Armed police shot a man with a stun gun after he walked into a Hertfordshire department store with a knife and stabbed himself.
Officers were called to the John Lewis store in the Harlequin Centre, Watford, on Wednesday.
Police said the man was shot for his own safety and that nobody else was injured.
He was taken by air ambulance to the Royal London Hospital in Whitechapel, where he is in a critical condition.
A Hertfordshire Police spokesman said: "Officers deployed 'Taser' for the man's own safety and he has been airlifted to hospital with serious injuries."
The spokesman said officers remained at the store after the incident at about 1300 BST and that investigations were continuing.
Gary Sanderson, of the East of England Ambulance Service, said two crews attended along with a doctor and paramedic from the Herts Air Ambulance, which landed at a nearby school.
"The man was rapidly treated and stabilised before he was airborne to the Royal London Hospital in Whitechapel where he is in a critical condition," he said.
Mr Sanderson said the man had received "extensive treatment" at the scene, including surgical procedures.
"The doctor on board (the air ambulance) is a specialist in trauma care and had a critical care paramedic working alongside him," he said.