I see the first Snowdrops in the garden are coming into flower. Galanthus species flower in late winter/early spring but these are rather early; the end of the month or beginning of February is more usual.
 London has a microclimate warmer than surrounding areas and I think we have in effect a nine month growing season. Even so the Snowdrops are ahead of time, probably because we've had a wet winter so far and no sub zero temperatures to speak of.