shortly after the outbreak of war on 4 august 1914, tf units were invited to volunteer for overseas service. meanwhile, the formation of a reserve or 2nd line unit was authorised for each 1st line unit where 60 per cent or more of the men had volunteered for overseas service. the titles of these 2nd line units would be the same as the original, but distinguished by a '2/' prefix. all the kfre units were initially employed on the thames estuary defences, but in june 1915 1/1st–1/3rd works companies left and were converted to field companies for service overseas; 1/6th and 1/7th companies also formed field companies that served in home defence. 4th and 5th el companies appear to have remained in the thames defences throughout the war.