Two police dogs, one of them a puppy, died when their handler left them locked in his car on one of the hottest days of the year.
The officer, Sergeant Ian Craven, one of the country's most experienced dog trainers, slashed his wrists when he learnt of their deaths.
He was taken to hospital after the apparent suicide attempt, and could now face prosecution for animal cruelty
It is the second time he has been responsible for the death of a dog left in a vehicle.
He was disciplined over the loss of a spaniel at the Metropolitan Police's prestigious dog training centre in July 2004 – but went on to be promoted.
In Sunday's incident the animals collapsed in the rear of his airless car as temperatures rose to 29c (84f) at the same training centre.
Staff pulled the Belgian malinois Chay and five-month-old alsatian Milly from the vehicle by smashing its closed windows.
They doused the dogs in water and raced them to an emergency vet but nothing could be done.
Kennel assistant, Tina Dale, 54, who was among those who tried to save the animals, described it as the 'worst day of my life'
She said on a social networking site: 'The suffering those dogs went through is too unbearable to think about. I'm in bits, we tried so so hard, but it was too long, the damage had been done. What a bloody awful way to die.'
Animal welfare charities called for Sergeant Craven to face the full force of the law.
Jan Creamer, head of Animal Defenders International, said: 'It is the golden rule that you never ever leave dogs in hot cars.
'While we do not doubt that this was a tragic accident, we would have thought that the Met Police dog unit should be setting an example to others.
'We would question why dogs were in the car at all as there are kennelling facilities on-site, we believe.
'Surely it should have been standard operating procedure to put the dogs in kennels on hot days
Chay was used by police for breeding and Milly was still being trained.
They were discovered in the back of Mr Craven's private estate car at the training centre in Keston, Kent, at 11am on Sunday.
The alarm was raised in a phone call from Mr Craven, who had travelled to work at the Olympic site in East London, several hours earlier.
He was on his way back to Keston with other officers when he was told that the animals had died.
He jumped from the car and fled. He was found by colleagues on a canal path after apparently attempting to take his own life and was taken to hospital.
Investigators from the RSPCA have begun an investigation which could lead to criminal charges. The Met's Directorate of Professional Standards are also looking into the incident and the Independent Police Complaints Commission have been informed.
Animal Cruelty is punishable by a maximum jail term of 51 weeks, a fine of up to £20,000 and a lifetime ban on keeping pets.
Sergeant Craven, who has more than 30 years' experience in the police was visited in hospital by Chief Superintendent Julia Pendry, of the Met's central operations wing which oversees the force's dog units.
In 2006 he featured prominently on a BBC Breakfast TV series about the work of handlers at the Met's centre.
Two years ago a Nottinghamshire police officer left two dogs to bake to death in his car. Constable Mark Johnson, 40, who left his two German shepherds to die in July 2009, was given a six-month conditional discharge and fined £2,500 last year.
Animal charities said dogs can die in as little as 20 minutes inside vehicles as temperatures quickly soar to 40c (104f).
An RSPCA spokesman said: 'In hot weather we would urge people never to leave dogs in vehicles for any length of time.'
Sources said an internal inquiry would consider a possible criminal prosecution.
PC Mark Johnson was given a six-month conditional discharge last year after leaving his two German Shepherds to die in the back of his car
The tragedy comes a year after a Nottinghamshire police officer was prosecuted when two German Shepherds died in the back of his sweltering car.
PC Mark Johnson escaped prison and was handed a six-month conditional discharge.
The 40-year-old returned to the force but is no longer working as a dog handler and was assigned to duties in south Nottinghamshire as an ordinary response officer
During his trial at Nottingham Magistrates' Court on February 22, the judge was told PC Johnson suffered from depression and obsessive compulsive disorder.
This led to him forgetting that he had left the dogs in his car which was parked at Nottinghamshire Police's Sherwood Lodge headquarters near Arnold on June 30 of 2009, the court heard.
During PC Johnson's February trial, the court heard he arrived at work with 18-month-old Jay-Jay and Jet, seven, on one of the hottest days of last year where temperatures peaked at nearly 30C.
He planned to move the two Alsatians into an air-conditioned police car but he got distracted and set about attending meetings and completing his paperwork.
Seven hours later, after a meeting with a sergeant about his mental health problems, the police officer remembered he had left them in the back of his own car and rushed out to find them dead.
The dogs suffered severe heatstroke and would have gone through 'excruciating pain' before they died of kidney failure and cerebral haemorrhage, the trial was told.
PC Johnson, a married father-of-one who has nearly 18 years' service, was suspended at the time of his trial. Police chiefs said following the verdict he would face an internal disciplinary panel.
Nottinghamshire Police was also severely criticised by district judge Tim Devas after it emerged PC Johnson was suffering from depression and OCD but found it difficult to get help.
His illness meant he simply forgot to move his dogs from his own black Ford Mondeo Estate, it was claimed.
He also regularly broke down in tears and was afraid to admit he might have a problem because he believed it could see him transferred off the dog section.
Sentencing PC Johnson, Mr Devas said: 'I have no doubt that had PC Johnson received the help he needed then he wouldn't be standing before me here today.'
Nottinghamshire Police received thousands of emails and calls from dog lovers after the case first hit the headlines last year.
It has since enforced a number of changes.
All dogs must be kept in kennels whilst at Sherwood Lodge and handlers have been given key fobs which alert them to any change in their car's temperature.
PC Johnson is currently paying off £2,500, a contribution towards the costs of the RSPCA's prosecution. But he has not been banned from keeping animals.
Read more: http://www.dailymail.co.uk/news/article ... z1QYvnNFBN