[7] The lighthouse was a much-needed aid to navigation due to the number of wrecks on the dangerous reefs of Whitburn Steel[8] which lay directly under the water in the surrounding area.

[9] Alongside the lighthouse tower a number of other buildings were laid out around a quadrangle, including the engine room and boiler house, and five dwellings; all were built of rubble masonry, rendered with Portland cement.

[15] An initial installation at Dungeness Lighthouse in 1862 had proved problematic, however, with frequent failures of the lamps and machinery; so Trinity House carried out an extensive testing and selection process over five years (including comparisons with oil lights and examination of equipment in Britain and France)[16] before finalising its plans for a complete purpose-built electric installation at Souter.

[3] The carbon arc lamp at Souter was placed within a lens array consisting of a third-order fixed catadioptric optic surrounded by a revolving assembly of eight vertical condensing-prisms which produced one bright flash every thirty seconds.

In normal operation only one generator was used, but in conditions of poor visibility both were connected to the lamp to provide a brighter light.

[21] Holmes also designed a reed fog signal for the new lighthouse, sounded from a separate foghorn house (east of the tower) through a pair of vertical trumpets (angled north-east and south-east, facing out to sea).

[3] In 1914 the pioneering electric light at Souter was replaced with the latest type of incandescent oil lamps (i.e. paraffin vapour burners).

[30] (These replaced the twin Holmes trumpets formerly employed; the foghorn house was remodelled at the seaward corners to accommodate them).

The mechanism which turned the lenses continued to be driven by clockwork at this time, until 1983 when it was replaced by a pair of electric motors.

The diaphone produced a five-second blast every 30 seconds in poor weather, and remained in use up until 1988, when the lighthouse was decommissioned.

[6] Souter Lighthouse was decommissioned by Trinity House in 1988,[34] but continued to serve as a radio navigation beacon up until 1999 when it was finally closed.

As Souter was never automated, it remains much in its original operational state except for updates during its lifespan to its lantern and electrical apparatus.

[6] Today the decommissioned Souter lighthouse is owned by the National Trust and open to the public; the engine room, light tower and keeper's living quarters are all on view.