In February 1941, Roelfzema wrote the so-called 'Leiden manifesto', which called on Leiden students to resist the occupying forces. He had it printed at his own expense and it was posted throughout the city on the night of 14 February. In April 1941, he spent a week imprisoned in the Oranjehotel in Scheveningen before escaping, going into hiding in Amsterdam and then managing to make his way to England. Roelfzema became involved in the 'Contact Holland' project that worked to improve communication with the resistance movement in the Netherlands. Along with Bob van der Stok, Chris Krediet and Peter Tazelaar, Roelfzema delivered transmitting equipment to the Dutch coast for use by resistance members. They also picked up people from the occupied Netherlands who were needed in England. The group used a motor gun boat belonging to the Royal Navy to travel close to the coast, completing the last leg of the journey to the beach with a rowing boat. Several missions failed due to the tide. In 1942, Roelfzema commenced pilot training and joined the 139th squadron of the RAF, flying 72 Pathfinder missions to Germany. At the end of the war, he was an aide-de-camp to Queen Wilhelmina, with whom he returned to Dutch soil on 2 May 1945. He was present during the Queen's triumphant return to The Hague on 6 July 1945 and also during the return of the young princesses on 2 August 1945. Roelfzema owes his nickname 'Soldier of Orange' to the book, film, TV series and musical of the same name that told the story of his life. A plaque by the beach at Scheveningen, on the Gevers Deynootweg, honours Roelfzema and the other Engelandvaarders. It reads: ‘In the winter of 1941-42, the Engelandvaarders Erik Hazelhoff Roelfzema, Chris Krediet and Peter Tazelaar made landings on this beach. The purpose of the landings was to establish reliable contact between the Dutch government in London and the resistance in the occupied Netherlands. During World War II, approximately 1,800 Engelandvaarders escaped to England via various routes to assist in the liberation of our country. In London, they were welcomed by Queen Wilhelmina, mother of the Engelandvaarders, who saw them as a link to the occupied Netherlands. During the war, she appointed Krediet, Tazelaar and Hazelhoff Roelfzema – who later became known as the Soldier of Orange – as her personal aides-de-camp.'