Southwell (pronounced south-well) is a small coastal village in Tophill on the Isle of Portland, Dorset.

[1][2] The Great Southwell Landslip, named after the village, remains Britain's second largest recorded historical landslide on the east side of Portland, occurring in 1734, between Durdle Pier and Freshwater Bay, at a distance of one and a half miles.

The various archaeological finds around the village include Iron Age earth defences and Roman stone sarcophagi.

[4] The island's wells and ponds could not cope, and so in 1890 work began on the digging of a deep shaft at Southwell for a new water supply.

The work continued until May 1895, however the shaft was dug too deep, the water turned brackish, and the scheme has to be abandoned.

[8] With the outbreak of World War II, a number of heavy anti-aircraft batteries were constructed to protect Portland's naval base, and Portland's HAA "C Battery" was built to the western outskirts of the village, at Barrow Hill.

[13] The establishment became infamous for the discovery of a Soviet spy ring that operated from the late 1950s until 1961 when the core of the network was arrested by the British security services.

[15] Throughout the 20th-century Southwell continued to remain a rural community, until the 1960s when major expansion saw many large housing and bungalow estates established.

[21] In September 2016, part of the site will be home to the Isle of Portland Aldridge Community Academy's £14 million campus, after an appeal overturned the decision of Weymouth and Portland Borough Council's planning committee to refuse permission for the build at Maritime House.