Shipwrecks are the nightmare we have forgotten - the price Britain paid for ruling the waves from an island surrounded by treacherous rocks. The result is a coastline that is home to the world's highest concentration of sunken ships. But shipwrecks also changed the course of British history, helped shape our national character and drove innovations in seafaring technology, as well as gripping our imagination.

The terrible toll taken by shipwrecks was such that in the winter of 1820 some 20,000 seaman lost their lives in the North Sea alone. That's 20 jumbo jets. But in the final part of his series, maritime historian Sam Willis tells the stirring story of how the Victorians were finally driven into action, finding various ingenious solutions - from rockets that could fire rescue lines aboard stricken vessels to lifejackets, lifeboats and the Plimsoll Line, which outlawed overloading.

In Africa, he traces the legend of the Birkenhead Drill - the origin of 'women and children first'. Decorum even in disaster was the new Victorian way and it was conspicuously on hand to turn history's most iconic shipwreck - Titanic - into a tragic monument to British restraint. Show less