While the dog attacked the police the owner and a friend did nothing, instead telling them: "You should have just knocked on the door", the jury was told.

Owner Symieon Robinson-Pierre ignored requests to call the dog off as it attacked the officers, instead going back inside with a friend and saying: "Mate, there's nothing we can do", it was alleged.

The powerfully built dog, which was finally killed with four shotgun blasts, had pounced after police went to the house in Stratford, east London, clamping its teeth into one officer's upper thigh.

The dog, weighing 29kgs, tried to drag him to the ground as another policeman repeatedly hit it in the head with a metal battering ram, to no effect.

He eventually prised the animal's jaws open with his baton but the dog turned on him grabbing hold of his right forearm and went on to attack other police in the front garden.

It was then Robinson-Pierre and another man appeared at the front door, Inner London Crown Court heard.

Prosecutor Sam Brown said: "One of the men answered with words to the effect of 'we can't, mate there's nothing we can do.'

"One of the men then said in a tone that was utterly sanguine 'you should have just knocked on the door.'

"After these vignettes were uttered the two men turned around, went back into the house closing no doubt what was left of the front door behind them."

Amateur video footage of the attack showed police clambering onto a narrow wall to try and escape the crazed dog, with the mauling only ending when a police marksman killed the animal with four shots.

The jury heard the dog left behind a scene of "carnage" in the terraced street.

Mr Brown said: "If you need a useful image in mind of the aftermath of this event, imagine the sickbay after the Battle of Trafalgar and that will give idea - carnage."

Robinson-Pierre, 25, denies four counts of being owner of a dog which caused injury whilst it was dangerously out of control in a public place.

The charges relate to the dog attack on Pc Marc Merritt, Pc Lee Bush, Pc Paul Garrard and Pc Steve Bones who were either attacked in the front garden or in the street as they tried to get the animal off their colleagues on March 22 of this year.

^{PC Martin Corderoy, PC Marc Merrit and PC Lee Bush at Inner London Crown Court Photo: Central News}

He is not being prosecuted for the initial attack on Pc Martin Corderoy as it happened inside the house.

Mr Brown told the jury: "This case concerns a horrifying episode in central London this year borne out of a criminal failure by a dog owner to firstly realise the risk his animal posed and secondly to be in a position because of that failure to properly restrain it.

"Through no fault of the animal's, its natural instinct manifested themselves in a terrifying display causing injury.

"No allegation is made that this defendant set his dog on these officers otherwise he would be facing very different charges.

"However, the conditions in which the dog was kept - the type of premises - the behaviour of the dog towards police officers in the house, and the defendant's own attitude towards persons being attacked outside, are all matters that you will want to consider when listening to the evidence in this case."

The dog first attacked PC Corderoy, before setting on PC Merritt and causing him to run screaming into the street, the court heard.

PC Bush freed Merritt, but as he shut the gate the dog leapt at him, continuing to attack as he sought refuge in a police van.

Another officer, PC Paul Garrard, leapt on a garden wall to get out of the way but was grabbed by the ankle.

Despite banging the dog's head in a door PC Garrard only escaped when he leapt on a car bonnet.

Others attempted to tackle the dog with riot shields, a fire extinguisher and batons but failed to subdue it .

Pc Bones grabbed the dog's throat to push it down but had his hand and fingers repeatedly bitten before it was eventually pinned down under a riot shield.

Mr Brown said: "For the first time it would appear the dog was under control. But only it would seem through exhaustion."

A firearms officer armed with a shotgun then shot the dog three times but it still struggled before a final shot to the head dispatched it.

He said all the officers that were bitten had to have surgery to "repairs the wounds to their bodies."

The trial expected to last five days continues.