Route 405 was previously part of the London Country South West network, operating from Crawley to West Croydon Station.
On 21 April 2001, it became a Transport for London route between Redhill and Croydon and it passed to Connex operating from their Beddington (BC) garage with brand new Plaxton Pointer 2 bodied Dennis Dart SLFs introduced.
On 20 August 2003, the route passed to Metrobus operating from their Crawley (CY) with brand new Plaxton Pointer 2 bodied Dennis Dart SLFs introduced.
On 16 April 2005, the allocation was transferred from Crawley (CY) to Godstone (GD) garages.
On 25 February 2006, Godstone (GD) Garage was announced closed and the allocation was transferred to Croydon (C) garage.
On 21 April 2006, the allocation was transferred from Croydon (C) to Crawley (CY) garages.
On 30 October 2006, the route was converted to double deck using new and existing Scania OmniDekkas.
On 1 September 2007, Schoolday only journeys were introduced between West Croydon and Purley operated by Arriva London from their Croydon (C) garage using a Wright Pulsar Gemini bodied DAF DB250LF.
On 30 August 2008, it was retained by Metrobus and the allocation was transferred from Crawley (CY) to Croydon (C) garages.
In July 2014, the Go-Ahead Group restructured its bus operations, which included the transfer of Route 405 from Metrobus to Go-Ahead London.
On 29 August 2015, the route was retained by London General with brand new Wright Eclipse Gemini 3 bodied Volvo B5LHs and Volvo B5TLs introduced.
Route 405 operates via these primary locations:
- Redhill Bus Station
- Coulsdon South
- Coulsdon Town
- Purley Cross
- South Croydon
- Wellesley Road
- West Croydon