Jonathan Freedland compares cyber-attacks today with the Great Siege of Dover Castle in 1216 during which the French used new offensive techniques to try to seize the English throne.

In 1216, Prince Louis of France's near-successful bid for the English throne climaxed in Dover, where his forces used a multitude of techniques in a major assault on the castle - including digging beneath the castle gate and use of the trebuchet to attempt to breach the walls. Jonathan draws on this medieval example to discuss cyber security in the 21st century context.

Joining Jonathan at Dover Castle are medieval historian Marc Morris; General Sir Richard Barrons, former Commander Joint Forces Command, one of the six Chiefs of Staff leading the UK Armed Forces until April 2016; Kenneth Cukier of The Economist; and Sara Perez, ethical hacker at SensePost. Readings are by Hugh Simon who played MI5 Data Analyst Malcolm Wyn-Jones in the popular BBC TV series Spooks.

Producer: Laurence Grissell.