A steady flow of refugees, prisoners of war and 1,177,125 wounded came back to England through Southampton. In 1919, soldiers returning from World War I mutinied in the port. In 1920, Bitterne Parish Council and Itchen Urban District Council, which collectively covered the districts of Bitterne, Bitterne Manor, Bitterne Park, Woolston, Peartree Green, Sholing and Weston, were incorporated into the borough of Southampton. Bassett and Swaythling were incorporated into Southampton at the same time. The period between the two World Wars saw an increase in the volume of traffic, as the motor car and Southampton Corporation Tramways evolved. It became essential to develop new routes around the Bargate as the central arch was too much of an obstruction. By 1931, a tram passed through the Bargate every 30 seconds and over the course of 14 hours, 2000 cars and 6000 bicycles would use the same narrow passage between Above Bar and the High Street. The photographs (below) illustrate the problem. Several old buildings and part of the medieval walls were demolished on both sides of the Bargate. In 1932, the Bargate was bypassed on its eastern side. The Bargate became an island when it was bypassed on its western side in 1938. The Clock Tower, further up Above Bar at the junction with New Road, was relocated to Bitterne Park Triangle in 1934 to facilitate further road improvements. On 26 March 1929, Southampton Corporation purchased Northam Bridge from the Northam Bridge Company. On 16 May 1929, the tolls on that bridge were removed. At the same time, the tolls at Lances Hill, Hedge End and the bridge at Bursledon were also abolished. The only remaining toll in Southampton was at the Floating Bridge, which was eventually taken over by Southampton Corporation in 1934, remaining a toll-crossing until it closed in 1977. The Second World War hit Southampton particularly hard. Pockets of Georgian architecture remain, but much of the city was levelled during the Blitz of November 1940. 476 tons of bombs were dropped on the city by the Luftwaffe. Southampton was a prime target because of its general strategic importance as a major port and industrial area, and particularly because the Supermarine Spitfire was designed, developed and built in Southampton. On 15 September 1940, the Supermarine factory in Woolston was bombed, killing many, though not damaging the factory. Two days later, the factory was destroyed. After the air raid Nazi propaganda declared that the town had been left a smoking ruin.