To most of us, the city of Portsmouth has only been in danger of attack during the Second World War.
The submarine boom defence, still in place east of South Parade Pier, was constructed during the First World War to stop German U-boats entering the harbour. And that is about all people know.
But there was another harbour boom defence put across the harbour mouth some time after 1518 during the reign of Henry VIII.
Bishop Fox of Winchester had written to Lord Chancellor Cardinal Wolsey saying that ‘if war were intended against England, the Isle of Wight and Portsmouth are too feeble for defence’.
Shortly after, work started on making a massive iron-linked chain to be drawn across the harbour mouth. It would be lowered and raised by capstan.
In 1533 John Leyland was appointed King’s Antiquary, the first to hold the post, and in 1543 he arrived in Portsmouth and described the chain defence thus: ‘There is this point of the haven (harbour entrance) Portsmouth town and a great round tower with another across the haven. Here there is a mighty chain of iron from tower to tower.’
It must have reassured local people, for France believed she could take the town because a massive fleet of 150 ships and 75 oared coasters with 60,000 men on board and only a little inferior to the mighty Spanish Armada that threatened the country 50 years later, was ready to strike at Portsmouth and the Isle of Wight.
On July 17, 1545, the English fleet of 100 ships went out to meet the French as they appeared off St Helens. With little room to manoeuvre ,the English withdrew to the harbour mouth and the French, knowing there was no point in trying to land until the English fleet had been crippled, sailed for home.
There was one great loss during the meeting, the carrack Mary Rose foundered within site of Southsea Castle and Henry VIII.
The chain remained in use for many years but was believed to have been dismantled in the 17th century.
Part of it was found in the 1930s by workmen digging alongside the Round Tower and a link is on show nearby.
What happened to the rest of it I do not know, but it must be somewhere.