Although the East Coast was attacked by the German High Seas Fleet on 16 December 1914 (the Raid on Scarborough, Hartlepool and Whitby) and again on 24 April 1916 (the Bombardment of Yarmouth and Lowestoft), and was regularly bombed by Zeppelin airships, the fortress engineers were nevertheless able to release 1st Line men to provide 1/1st East Riding Field Company, RE for active service in the field. A 581st (Humber) Fortress Company was also formed, about which little is known.