Major General Count Albert-Marie Edmond Guérisse (5 April 1911 – 26 March 1989) was a Belgian Resistance member who organized French and Belgian escape routes for downed Allied pilots during World War II under the alias of Patrick Albert "Pat" O'Leary, purportedly the name of a peace-time Canadian friend. His escape line was dubbed the Pat O'Leary Line.
Guérisse was born in Brussels, and qualified in medicine at the Université Libre de Bruxelles before joining the Belgian Army. Guérisse was Médecin-Capitaine with a Belgian cavalry regiment during their eighteen-day campaign in May 1940. He managed to escape to England through Dunkirk. At Gibraltar, he joined the crew of a former French merchant ship, Le Rhin, which was later renamed and served in the Mediterranean on clandestine missions. He secured entry into the British Royal Navy and was commissioned as Lieutenant Commander Patrick Albert O'Leary RNVR of French-Canadian origin. The "Canadian" identity attempted to explain his not-quite British accent in English, and his not-quite French accent in French, in order to protect his family in occupied Belgium if he was captured. He had a six-week undercover training session with Naval Intelligence. Until April 1941, he was serving mainly as a conducting officer, escorting agents ashore in small boats through the surf, whilst the large vessel lay some distance offshore. This was skilled work, exposed to physical dangers from the sea-conditions and operational dangers from the Vichy security services.
On 25 April 1941, during a mission to place Special Operations Executive (SOE) agents in Collioure, on Roussillon coast in southern France, "O'Leary" and three crewmen from HMS Fidelity were arrested by the Vichy French coast guard and taken to a camp for British military prisoners at Saint-Hippolyte-du-Fort near Nîmes. Helped by 'fellow British' officers, "O'Leary" escaped in early June 1941. He went to Marseilles where there was an escape organisation run by a British Army officer, Ian Grant Garrow, and soon made contact.