A cash and carry employee was blasted in the chest with a shotgun at point-bank range as he tried to stop a gang of armed robbers.
Colin Thomas, 24, was fighting for his life in hospital today after the raid at a branch of Costco, in Croydon, south London.
A gang of five masked raiders wearing hoods and scarves ran into the busy warehouse store at about 7.40pm last night.
They made off with a haul of jewellery after smashing several glass cabinets with a hammer.
Alerted by an automatic alarm, Mr Thomas ran to stop them but was shot by one of two men guarding the main exit.
Colleagues described Mr Thomas, recently promoted to supervisor, as a "phenomenal" worker and "role model".
Speaking outside the store today, Detective Superintendent Bob Cummings, of the Flying Squad, paid tribute to his bravery.
He said Mr Thomas probably reacted "instinctively" after hearing the alarms and seeing the commotion.
Mr Cummings said: "He is in a serious condition. We are very concerned about him. Costco employees are very concerned about him and his family are with him.
"He has worked for Costco for five months and has already been promoted in that short time.
"He is an intelligent man who acted extremely courageously on this occasion.
"It is very sad, a promising career, a man just carrying out his job, should have this happen to him."
Mr Cummings said it is not yet known how much the stolen jewellery was worth. He declined to give further details.
Sources close to the store said the total value of the missing jewellery could be hundreds of thousands of pounds.
It is believed to include a large number of Rolex watches and expensive gold, platinum and diamond rings.
Describing the robbery, the officer said five men described as black and wearing hoods and scarves ran inside the store.
He said: "Two remained by the door and the other three made their way to the jewellery cabinets where they smashed the displays and stolen items of jewellery.
"They have then made their way towards the exit. An alarm has been activated when the display cases were smashed.
"That has alerted a couple of members of staff, including Colin Thomas, a supervisor in the store.
"They have pursued the three towards the exit and at the exit Mr Thomas has been confronted by one of the two men guarding the door.
"That man has fired a shot with a shotgun at point-blank range and has injured Mr Thomas who has been taken to hospital and treated overnight.
"The five suspects then fled towards the playing fields on Purley Way. We have not got a great deal of other details to inform us about their escape.
"It is a busy store, it was 7.40pm, there is likely to have been a lot of people around, not just the store, but escape routes as well.
"We are appealing to anyone who saw anything to come forward and give us information about it."
Mr Cummings said Mr Thomas underwent emergency surgery overnight and his girlfriend is by his side.
He said the suspects are likely to have escaped in a vehicle as the shop is adjacent to the busy A23 and other routes.
The senior detective said the men are also likely to have visited the store before to prepare the robbery.
Mr Cummings said the second man guarding the exit may also have been carrying a weapon.
He said: "There must be a degree of planning involved in this robbery. If you were planning a jewellery robbery Costco is probably not the first place you would choose.
"By the two men remaining by the door, because the display cabinets are not by the door, this would suggest they have undertaken planning reconnaissance in the past."
A large area of the car park remained cordoned off today and search teams were continuing to examine the large store.
Police have seized CCTV footage and are examining images from other companies on the business estate.
Store manager Martin Sandler said of Mr Thomas: "He was a role model, a phenomenal worker. He had just been promoted to supervisor."
Asked about his condition, he replied: "He is not out of the woods yet."
A fellow Costco employee added: "Our thoughts are with our colleague who was injured and remains in hospital. We are just hoping he makes a full recovery."
* Anyone with any information is asked to call the Flying Squad on 0207 232 5630 or Crimestoppers on 0800 555 111.Reuse content