It lies on the coast at the mouth of the Seaton Burn (a small river), midway between Whitley Bay and Blyth.

Before 1550 the salt produced at Hartley Pans had been transported to Blyth to be exported, but after that date it was shipped directly from the small, natural harbour.

This problem was tackled by Sir Ralph Delaval (1622–1691), who had a pier constructed, and sluice gates that trapped the seawater at each high tide.

The new entrance proved to be a success and, in 1777, ships sailed out of the harbour carrying 80,000 tonnes of coal, 300 tons of salt and 1.75 million glass bottles.

[9] In 1763 Sir Francis Blake Delaval (1727–1771) obtained Parliamentary approval to develop 25 acres (10 ha) of land at Seaton Sluice as glassworks.

[10] The glassworks expanded with time and eventually had six large cone-shaped furnaces which dominated the skyline; they were given the names: Gallagan, Bias, Charlotte, Hartley, Waterford and Success.

A distinctive feature was that the main mast could be lowered, allowing them to pass under the arches of old London Bridge.

The bottleworks were so large that they contained a market place, a brewery, a granary, a brickyard, a chapel, shops, public houses and a quarry.

Meanwhile, competing ports such as Blyth, to the north, and the Tyne to the south spent money improving the dock facilities.

However, in 1862, the beam of the pumping engine broke and fell down the only mineshaft, blocking it and trapping the miners underground.

The loss of production from the Hester Pit spelled the end of the coal trade from Seaton Sluice and it became a quiet backwater.

There is a memorial obelisk to the 204 men and boys who died in the graveyard of St Alban’s Church in the nearby village of Earsdon.

In the early 18th century the manor house was replaced by the present Seaton Delaval Hall, designed by architect Sir John Vanbrugh.

The hall, which is a Grade 1 listed building, is now owned by the National Trust and is open to visitors on designated days.

This was built by Sir Francis Delaval in 1750, according to legend after accepting a bet that he could build a home for a lady friend in a day.