The London to Brighton Way, also called the London to Portslade Way, is a Roman road between Stane Street at Kennington Park and Brighton (or more specifically Portslade) in Sussex. The road passes through Streatham and Croydon, then through the Caterham Valley gap in the North Downs. It passes through Godstone and Felbridge, then follows an almost straight line through Ardingly, Haywards Heath, Burgess Hill and Hassocks to the South Downs at Clayton. At Hassocks it crosses the Sussex Greensand Way at a large Roman cemetery. It climbs the South Downs escarpment, crossing the ridgeway and connecting with other local tracks. South of Pyecombe the route is uncertain, and may have continued to Brighton or to Portslade.
The road passed through some of the strategically important iron producing areas of the Weald and was partly constructed from iron slag in those areas, although to a lesser extent than the London to Lewes Way.
A number of Anglo-Saxon place names are clues to the road's existence; Streatham in London, and near Godstone, Stanstreet (now renamed Stanstead) and Stratton are indicative of a paved road already in existence when the settlements were founded. There was some traditional memory of a Roman road at Caterham, Croydon and Ardingly. In 1779 a schoolmaster from Lindfield, Stephen Vine, witnessed flint being taken from an ancient road to build a turnpike road. He published a report on the line from Clayton to north of Burgess Hill in The Gentleman's Magazine in 1781. In 1818 Reverend James Douglas looked at these findings and surmised that this was part of a road to a port in the Portslade area. This led to the surmised route being named the London to Portslade Way. Ivan Margary believed Brighton Old Steine, allowing for coastal erosion since Roman times, to have been more suitable as the destination port and called it the London to Brighton Way. Work in the mid 20th century established the route from London to Hassocks, but south of this there was still uncertainty. A paper published in 1999 by Glen Shields on the topography of the Hassocks and Clayton area concludes that the road took a more westerly route over Clayton Hill than proposed by Margary, and that a traceable route to Portslade would have been more practical and more in keeping with Roman practice elsewhere than going along the valley bottom to Brighton.