A large counter-attack was mounted on the French front on 22 March, which forced French cavalry and cyclists back over the Crozat Canal with many casualties but began too soon to ambush a large force that included artillery, as had been intended. A Booby-trap exploded in Bapaume town hall on 25 March, killing Australian troops and two French Deputies; French civilians were left behind at Bouvincourt, Vraignes and Tincourt on 26 March and Villers Faucon, Saulcourt and Guyencourt were lost on 27 March, to attacks by British cavalry and armoured cars. Supplies of armour-piercing bullets had been sent forward by the Germans after Roisel was captured the day before, resulting in the armoured cars being peppered with bullet-holes. The armoured cars decoyed the German defenders, while cavalry got round the flanks and captured the villages. Outpost villages close to the (Hindenburg Line) south of Quéant had to be held by the Germans for longer than expected, because of the need to complete the additions to the defences being built to remedy defects in the original position. Heudicourt, Sorel and Fins were lost on 30 March. The northern outpost villages were lost on 2 April and Lempire fell on 5 April.