The facts are worthy of a 21st century crime novel: an ungodly priest murdered by an aristocrat seeking revenge; and a jury too scared to identify the perpetrators.

But this is what happened nearly 700 years ago, when churchman John Forde had his throat cut in London's most prominent Medieval 'murder' hotspot - near St Paul's Cathedral.

Now, records traced by an expert criminologist suggest the priest's murder was a revenge killing orchestrated by a noblewoman who is believed to have been his lover.

Aristocrat Ela Fitzpayne allegedly directed four men - including her own brother - to cut down Forde in the belief that he betrayed her to the Archbishop of Canterbury.

A letter sent in 1332 by the Archbishop, then Simon Mepham, accused her of having sexual liaisons with 'knights and others, single and married, and even with clerics in holy orders.'