In 2008, the Department for Transport announced that 31 of the existing 9-car sets would be lengthened to 11 cars to increase capacity. Four new 11-car sets were also to be built. The longer units required major infrastructure changes to allow stations and depots to accommodate the 11-car units. With the closure of the Washwood Heath works, the additional vehicles were manufactured at Savigliano. The first new sets were built with 11 cars and delivered in December 2010. The lengthening project was completed in December 2012.