A third of all house fires in London are categorised as ‘severe’ causing £120m of damage.

Figures released by London Fire Brigade found that more than 2,000 homes across the capital are being lost to fires each year.

The brigade has designed an index, which ranks fires as ‘severe’, ‘significant’, ‘moderate’ or ‘slight’. It shows that between October 2010 and September 2011, 2,257 fires - a third of all house fires - were classed as severe. The period showed there were also 2,335 significant fires and 1,656 moderate fires.

A severe fire is categorised as a fire which has rendered a property uninhabitable for any period of time. It will also have taken firefighters more than 45 minutes to bring under control. Some homes may be uninhabitable for a few days but in the worst cases, homes are completely destroyed.

The brigade estimates that the cost of a severe fire is around £60,000. This means that each year severe fires cost around £120million in temporary accommodation and restoration work.

Research also found that 21% of severe fires were caused by electrical faults, 16% were caused by cooking being left unattended, and 10% were caused by careless disposal of cigarettes.