The bridge is also the site of defensive structures dating to World War II, including a pillbox disguised as an agricultural cowshed and Dragon's teeth tank traps at its northern end.

[7] At the outbreak of World War II, plans were made for the defence of Britain in the event of a German invasion.

[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.

[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.

[15] Scourfield and Haslam, in their Powys volume of the Pevsner Buildings of Wales, describe Llandrinio as a "humped narrow roadway, yet a most graceful line when seen from the [river] bank.