At the outbreak of World War II, plans were made for the defence of Britain in the event of a German invasion. In the west, a defensive line, Western Command Stop Line No.1, followed the line of the Severn from Tewkesbury to Shrewsbury.[8] The line crossed the river at Llandrinio, and the bridge was fortified with a pillbox disguised as an agricultural shed and Dragon's teeth tank traps at its northern end.[9]
The Severn at Llandrinio is susceptible to flooding, which can lead to frequent closure of the bridge.[10][11][12] In 2015, particularly severe flooding led to fears that the bridge was at risk of collapse.[13] Subsequent investigations showed that several of the bridge's keystones had been removed by the floodwaters and a major programme of structural repair was required.[14]