On 26 May 1940, following the German invasion of Holland, Belgium and France, the Ministry of Health wrote to the Town Clerk declaring Dover an evacuation area and advising the early removal of school children. That same evening the Admiralty signalled the start of Operation Dynamo - the evacuation of the troops stranded on the beaches at Dunkirk.At the height of the Dunkirk operation the evacuation of the children commenced. At 7:45 am on Sunday 1st June the first train carrying 707 children to safety in South Wales pulled out of the Priory Station. By the end of the day 2899 children along with 235 teachers and helpers had left the town.In the days and weeks that followed many mothers with babies and people who had no need to remain in the town left for safer parts of the country. Although 600 infants and 624 children between the ages of 8 and 14 remained in Dover at the insistence of their parents, the population of the town was reduced from 40,000 to 15,000 within a few weeks.