Firefighters have issued a stark warning after arsonists struck at a derelict house for the third time in a week.

Crews from Hainault, Ilford and Redbridge tackled the blaze at the building, near Romford Road, Hainault, last night (Monday) at 6.30pm.

Large flames destroyed an upper floor and much of the roof of the unsafe house, leading to fears that the two-storey building could collapse. It is one of two ramshackle, unoccupied buildings within the country park that have repeatedly fallen victim to arsonists.

A firefighter who was at the scene of the fire said: “These houses are unsafe structures and we have been there three times this week.

“People are going into the houses and starting fires. If they people keep doing it they are going to hurt themselves and the houses are getting so damaged that we may not be able to get them to get anybody out.”

Crews called in a borough surveyor late last night who declared the scene of the fire unsafe.