After the Fall of France in May 1940, the Polish Army in Scotland was reorganised as the 1st Polish Corps and entrusted by the War Office with the defence of a long stretch of the country's east coast between Arbroath (later extended to Montrose, 38 miles (61 km) north of Dundee) and Burntisland on the Firth of Forth against a possible invasion from German-occupied Norway. The Poles strengthened existing defences by installing anti-tank obstacles, building pill boxes and patrolling the coastline in armoured trains. In early 1942 they gave up responsibility for Angus, taking over instead the defences of East Lothian.