<P> The Indian III Corps under Lieutenant - General Sir Lewis Heath--including the Indian 11th Infantry Division under Major - General B.W. Key with reinforcements from the 8th Indian Brigade, and the British 18th Division--was assigned the north - eastern sector, known as the "Northern Area". This included the naval base at Sembawang . The "Southern Area"--including the main urban areas in the south - east--was commanded by Major - General Frank Keith Simmons . His forces consisted of elements of the 1st Malaya Infantry Brigade and the Straits Settlements Volunteer Force Brigade with the Indian 12th Infantry Brigade in reserve . </P> <P> From 3 February, the Allies were shelled by Japanese artillery and air attacks on Singapore intensified over the next five days . The artillery and air bombardment strengthened, severely disrupting communications between Allied units and their commanders and affecting preparations for the defence of the island . From aerial reconnaissance, scouts, infiltrators and high ground across the straits, such as at Istana Bukit Serene and the Sultan of Johor's palace, the Japanese commander--General Tomoyuki Yamashita--and his staff gained excellent knowledge of the Allied positions . Yamashita and his officers stationed themselves at Istana Bukit Serene and the Johor state secretariat building--the Sultan Ibrahim Building--to plan for the invasion of Singapore . Although advised by his top military personnel that Istana Bukit Serene was an easy target, Yamashita was confident that the British Army would not attack the palace because it belonged to the Sultan of Johor . Yamashita's prediction was correct; despite being observed by Australian artillery, permission to engage the palace was denied by their commanding general, Bennett . </P> <P> It is a commonly repeated misconception that Singapore's famous large - calibre coastal guns were ineffective against the Japanese because they were designed to face south to defend the harbour against naval attack and could not be turned round to face north . In fact, most of the guns could be turned, and were indeed fired at the invaders . However, the guns--which included one battery of three 15 in (380 mm) weapons and one with two 15 in (380 mm) guns--were supplied mostly with armour - piercing (AP) shells and few high explosive (HE) shells . AP shells were designed to penetrate the hulls of heavily armoured warships and were mostly ineffective against infantry targets . Military analysts later estimated that if the guns had been well supplied with HE shells the Japanese attackers would have suffered heavy casualties, but the invasion would not have been prevented by this means alone . </P> <P> Percival incorrectly guessed that the Japanese would land forces on the north - east side of Singapore, ignoring advice that the north - west was a more likely direction of attack (where the Straits of Johor were the narrowest and a series of river mouths provided cover for the launching of water craft). This was encouraged by the deliberate movement of enemy troops in this sector to deceive the British . As such a large portion of defence equipment and resources had been incorrectly allocated to the north east sector, where the most complete and freshest formation--the British 18th Division--was deployed, while the incomplete Australian 8th Division sector with just two brigades had no serious fixed defensive works or obstacles . To compound matters, Percival had ordered the Australians to defend forward so as to cover the waterway, yet this meant they were immediately fully committed to any fighting, limiting their flexibility, whilst also reducing their defensive depth . The two Australian brigades were subsequently allocated a very wide frontage of over 18 kilometres (11 mi) and were separated by the Kranji River . </P>

Who helped the british troops defend malaya and singapore