http://www.telegraph.co.uk/news/uknews/1584210/April-snow-worst-for-two-decades.html
In Spring 2008, parts of the UK (even in the south) received up to 3 inches of snow. This is particularly odd since the UK is a country that receives almost no snow even during the winter months due to prevailing warm air coming from the jet stream.
Met office synopsis (https://www.metoffice.gov.uk/climate/uk/summaries/2008/april):
"During the 5th, a cold front cleared southwards introducing much colder conditions to all parts. Northerly winds brought temperatures down and also some increasingly wintry showers. During the 6th an area of sleet and snow moved across much of the Midlands and SE England with 5 to 10 cm reported fairly widely, causing Heathrow airport to close for a time."