The London Night Bus network is a series of night bus routes that serve Greater London. Services broadly operate between the hours of 23:00 and 06:00. Many services commence from or operate via Trafalgar Square and are extensions or variations of daytime routes and hence derive their number from these; for example, route N73 Oxford Circus to Walthamstow follows that of route 73 as far as Stoke Newington, before continuing further north.