According to Tacitus, the British horde first sacked London, then swept northward to ravage Verulamium (St Albans). Suetonius, meanwhile, retreated north along Watling Street to join the Roman infantry on its return south- eastward from northern Wales.
Historians generally agree that the engagement leading to the defeat of the British, and Boudicca's subsequent death by self-poisoning, took place at an unknown spot in the Midlands, on the line of the A5. The name of London's Battle Bridge (now King's Cross) is thought to be, prosaically, a corruption of an earlier "Bradford" (or broad ford).
Associate Editor, "Camden History Review"