Army was ready; and began the offensive against the and of the . Prelude British plan Operation Lightfoot Montgomery's plan was for a main attack to the north of the line and a secondary attack to the south, involving XXX Corps (Lieutenant-General Oliver Leese) and XIII Corps (Lieutenant-General Brian Horrocks), while X Corps (Lieutenant-General Herbert Lumsden) was to exploit the success. With Operation Lightfoot, Montgomery intended to cut two corridors through the Axis minefields in the north. One corridor was to run south-west through the 2nd New Zealand Division sector towards the centre of Miteirya Ridge, while the second was to run west, passing north of the west end of the Miteirya Ridge across the 9th Australian and 51st (Highland) Division sectors. Tanks would then pass through and defeat the German armour. Diversions at Ruweisat Ridge in the centre and also the south of the line would keep the rest of the Axis forces from moving northwards. Montgomery expected a 12-day battle in three stages: the break-in, the dogfight and the final breaking of the enemy. For the first night of the offensive, Montgomery planned for four infantry divisions of XXX Corps to advance on a front to the Oxalic Line, over-running the forward Axis defences. Engineers would clear and mark the two lanes through the minefields, through which the armoured divisions from X Corps would pass to gain the Pierson Line. They would rally and consolidate their position just west of the infantry positions, blocking an Axis tank counter-attack. The British tanks would then advance to Skinflint, astride the north–south Rahman Track deep in the Axis defensive system, to challenge the Axis armour. The infantry battle would continue as the Eighth Army infantry "crumbled" the deep Axis defensive fortifications (three successive lines of fortification had been constructed) and destroy any tanks that attacked them. Operation Bertram Before the battle the Commonwealth forces practised deceptions, in Operation Bertram, to confuse the Axis command as to where and when the battle was to occur. In September, they dumped waste materials (discarded packing cases, etc.) under camouflage nets in the northern sector, making them appear to be ammunition or ration dumps. The Axis naturally noticed these but as no offensive action immediately followed and the "dumps" did not change in appearance, they were subsequently ignored. This allowed the Eighth Army to build up supplies in the forward area unnoticed by the Axis,