pier was found to be intermittent so the gas light was soon replaced by a Chance Brothers incandescent petroleum vapour mantle lamp. This increased the effective intensity of the light from 40,000 to 150,000 candle power, to give it a range of . A fog siren was also provided, powered by compressed air from a pair of 7-horsepower gas engines located in the basement. It gave a two-second blast every twenty seconds in foggy weather from a sounder on the parapet, which was regulated by clockwork. The light was semi-automated in 1936 when a new light system was installed by AGA. The main lamp was a 750-watt incandescent light bulb, with a gas mantle lamp (fed from the town supply) provided as a stand-by, activated by an automatic lamp changer; and a small electric motor automatically wound the clockwork which rotated the lens. Full automation followed in 1972, when the old optic was replaced by two back-to-back arrays of six sealed beam units mounted on an AGA gearless rotating pedestal, to give the light an increased range of ; a new fog horn was also provided at the same time. The system was supervised remotely from the Pilot House on the Old North Pier. Subsequent to its removal the 1903 optic was added to the maritime collection of Sunderland Museum and Art Gallery. In 2007 the lighting system was again replaced with a dual-drive Pelangi PRL400 rotating pedestal and lamp. Roker Pier Lighthouse still functions today. Both pier and lighthouse have undergone significant refurbishment in recent years. In 2012, as part of the restoration, a new flashing LED lamp array was installed, replacing the small Pelangi unit previously in use. In 2018, following a comprehensive six-year process of refurbishment, the lighthouse was opened to the public for the first time; regular guided tours now take place, with access provided by way of the tunnel which runs the length of the pier. Demographics The population of Roker is approximately 4,600. Since the redevelopment of former brownfield areas of heavy industry into affluent riverside housing areas, and the founding of the St Peters Campus of the University of Sunderland to the immediate south of the area, Roker has undergone rapid demographic change. The first of these two changes brought a large influx of professional and managerial workers into the areas now known as St Peters Riverside and North Haven. The arrival of