part of a plan to use Gatwick Express services to provide extra capacity on the Brighton Main Line south of Gatwick Airport. Because the Class 460 fleet was too small to support both the extension to Brighton and the existing 15-minute frequency, Southern leased and refurbished a number of units work alongside the Junipers when the extended timetable took effect in December 2008. Following the June 2009 renewal of their contract to operate the South Central franchise, Southern leased and refurbished the remainder of the Class 442 fleet for use on Gatwick Express services. This enabled the gradual withdrawal of the Class 460 fleet, which began in 2010 and was completed by September 2012. Conversion to Class 458/5 South West Trains, operators of the South Western franchise from 1996 to 2017, had been experiencing a considerable shortage of passenger capacity on many of its suburban routes in the years immediately prior to 2012, which it attributed primarily to the fact that passenger numbers had increased dramatically without a corresponding increase in the size of their fleet. The company had suggested to the Department for Transport on at least three occasions that their fleet of units should be enlarged, but had been turned down each time. Rolling stock lessors Porterbrook, owners of the Class 460 fleet, also owned the fleet of Alstom Juniper units that had been in use with South West Trains since February 2000. As an alternative to ordering new trains for SWT, Porterbrook proposed to enlarge the Class 458 fleet and reconfigure it for suburban services by using vehicles from the now-redundant Class 460 fleet. The process, budgeted at £42 million, would use 30 of the 48 Class 460 intermediate cars to extend each of the original 30 Class 458 units to five cars each, leaving six Class 460 units that had been reduced to five cars each. These would be comprehensively rebuilt to match the extended Class 458 units, for a total fleet of 36 five-car units that would be designated Class 458/5. The units of this "new" fleet would be used—either individually or in pairs of ten cars—to provide extra peak-time capacity on suburban services to and from . The Department for Transport announced in December 2011 that it had accepted the proposal, and an agreement between Porterbrook and South West Trains was signed in January 2012. SWT's fleet director noted that while the project was