"The Arctic has been experiencing very cold temperatures this year, so it was an unusually cold front. Some unusual wind patterns meant it was blown over Britain very quickly, meaning the temperatures stayed very low. It is certainly very, very unusual to see snow in London this early," said Mr Chalcraft. "The last time there was October snow [in the South-East] was in 1974, but the last time we actually had snow cover in October [in London], which we did late last night, was in 1934."