How fast you dial 999 when fire breaks out is literally a matter of life and death, a report has warned.

Delays in ringing emergency services led to 95 per cent of deaths in accidental fires in the home last year, London Fire Brigade says.

Firefighters were called immediately in only two of the 39 accidental fatal dwelling fires in the capital.

In four of these fires, there was a delay of over an hour.

The report concludes that in 27 of the 39 fire deaths in the capital last year, the victims had most likely already sustained life-threatening injuries by the time firefighters were called.

The report also found there were no working smoke alarms in half of all accidental fires in the homes.

London fire commissioner Dany Cotton said: “This report suggests that there was a delay in calling the brigade or people weren’t aware that the fire had broken out until it was too late.

“Calling 999 and having a smoke alarm are the very basics of fire safety. If there is a fire in your home please do not try and tackle it yourself. Get out, stay out and dial 999.

“You should have a number of smoke alarms in your home and test them regularly.

"Don’t stick one alarm in your hallways and forget about it. Homes need multiple smoke alarms to give you the earliest warning of a fire."

She added: “Ideal spots for smoke alarms include rooms where you leave electrical equipment running like satellite boxes, computers or heaters; any room where you smoke, and anywhere you charge your mobile or laptop.

"As a minimum you should have smoke alarms on every floor - in the hallways and the rooms you use the most. It is vital that people regularly test their smoke alarms once a month.

“Our free home fire safety visits where firefighters give life saving advice has meant that 350,000 smoke alarms have been installed in homes over the past five years.”

Most fatal fires at home happen in the bedroom or the living room - with discarded cigarettes being the most common cause.

The report found nine per cent of fires start in the bedroom and six per cent in the living room, yet they account for 27 of the 39 deaths.

Overall, 44 people died from blazes in 2016/17.

But the report only looks at the 39 dwelling fires that were accidental and therefore probably preventable.

The remaining five deaths were from deliberate fires such as arson or suicide.

As part of its work to stop fires from breaking out in the first place, London Fire Brigade exceeded its target of 73,500 home fire safety visits last year.

More than half of the 84,500 visits were carried out in social housing accommodation, they said.

The brigade’s 2013 report concluded that people were 18 times less likely to have a fire if they had a home fire safety visit.

Firefighters said they focus visits on vulnerable people who have lifestyle characteristics that put them at greater risk from fire, or live in areas with higher risk.

The brigade said deaths as result of the Grenfell Tower fire will be included in next year’s figures.