These first trench maps, used until the Summer of 1915, also suffered from a lack of standardization. In the absence of a single, theatre-wide format for trench maps, some rather idiosyncratic patterns came into being in these early days of trench warfare. For example, on the British 1st Army Front, troops used the notorious maps that the intelligence officer Col. Charteris favored, which actually printed the North on the bottom and the East on the left-hand side of the map! In addition, the inverted Charteris maps lacked an over-printed grid with hash-marks, so that individual targets required individual target reference numbers. The British Army had to fight two of the largest early battles of the war, those of Aubers Ridge and Festubert, using these wholly unsatisfactory maps.