Churchill Barriers

The Churchill Barriers are a series of four causeways in the Orkney Islands, United Kingdom, with a total length of 1.5 miles (2.3 km). They link the Orkney Mainland in the north to the island of South Ronaldsay via Burray and the two smaller islands of Lamb Holm and Glimps Holm.

The barriers were built in the 1940s primarily as naval defences to protect the anchorage at Scapa Flow, but now serve as road links, carrying the A961 road from Kirkwall to Burwick.

The barriers are numbered from north to south. In 2016, Historic Environment Scotland designated barriers 3 and 4 as Category A listed buildings.

On 14 October 1939, the Royal Navy battleship HMS Royal Oak was sunk at her moorings within the natural harbour of Scapa Flow in a nighttime attack by the German U-boat U-47 under the command of Günther Prien. Shortly before midnight on the 13 October the U-47 had entered Scapa Flow through Kirk Sound between Lamb Holm and the Orkney Mainland. Although the shallow eastern passages had been secured with measures including sunken block ships, booms and anti-submarine nets, Prien was able to navigate the U-47 around the obstructions at high tide. He then launched a surprise torpedo attack on the unsuspecting Royal Navy battleship while it was at anchor in Scapa Flow. The U-47 then escaped seaward using the same channel by navigating between the block ships.

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