On 25 September 1993, the contract for route 4 was won by London Suburban Bus, who operated the route with Leyland Titans.

On 27 April 1995, route 4 was included in the sale of London Suburban Bus to Metroline and in March 2000 to DelGro Corporation.

On 15 June 2019, route 4 was rerouted to run between Archway station and Blackfriars.
On 25 September 1993, the contract for route 4 was won by London Suburban Bus, who operated the route with Leyland Titans.
On 27 April 1995, route 4 was included in the sale of London Suburban Bus to Metroline and in March 2000 to DelGro Corporation.
On 15 June 2019, route 4 was rerouted to run between Archway station and Blackfriars.
London Buses route 4