Major General Count Albert-Marie Edmond Guérisse 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.

The Pat O'Leary Line was a resistance organization in France during the Second World War. The Pat O'Leary escape line helped Allied soldiers and airmen stranded or shot down over occupied Europe evade capture by Nazi Germany and return to Great Britain. Downed airmen in northern France and other countries were fed, clothed, given false identity papers, hidden in attics, cellars, and people's homes, and escorted to Marseille, where the line was based. From there, a network of people escorted them to neutral Spain. From Spain, British diplomats sent the escapees home from British-controlled Gibraltar. Many different escape lines were created in Europe of which the Pat Line was the oldest and one of the most important. Collectively, the many escape lines helped 7,000 Allied military personnel, mostly airmen, escape occupied France, Belgium, and the Netherlands. The Pat Line received financial assistance from MI9, a British intelligence agency.