A grass fire ripped across an area of Mitcham Common "three times the size of Trafalgar Square" yesterday.

An estimated three hectares of grassland near the Croydon Road border was burnt out in the blaze.

Fourteen firefighters and three fire engines arrived just after 4pm and took nearly an hour and a half to extinguish the flames.

Police were called just before 5pm and closed roads around the Common. They were re-opened by 5.30pm when the fire was brought under control.

A Met spokesman said the fire was not being treated as suspicious.

Grass fires are most commonly caused by discarded cigarettes. But they can also be started by glass bottles which refract sun rays onto dry grass and shrubbery.

A London Fire Brigade spokesman said: "Grass fires can be started deliberately or accidentally, but however they start, they can cause huge damage to property and kill wildlife.

"If you see a grass fire, don't attempt to put it out yourself as grass fires can travel very quickly and change direction without warning. Call the fire brigade and let us know where the fire is."

Tips on preventing grass fires:

Never leave camp fires or barbecues unattended and extinguish them properly after you have finished using them.

• Clear away bottles, glasses and any broken glass to avoid them magnifying the sun and starting a fire.

• Dispose of smoking materials such as cigarettes safely.

• Explain to children the dangers of playing with and lighting fires.

Did you witness the fire? Call Louisa on 020 8722 6335, or email louisa.clarence@london.newsquest.co.uk.