A devastating fire which ripped through Canterbury Cathedral in 1174 was started deliberately by envious monks, a medieval historian has claimed.

Dr Emma Wells believes a bitter rivalry between two of England’s grandest cathedrals, Canterbury and Durham, turned ugly as they both sought to become the country’s most popular place of worship.

In her new book Heaven on Earth, the historian stresses her belief that monks based at Canterbury purposely set fire to their own cathedral so they could then build an elaborate crypt which would draw in visitors, and more importantly, compete with Durham.

Before the great blaze, Durham had the upper hand in terms of popularity.

Its extravagant architecture, and the fact the well-liked St Cuthbert was its saint, meant it was England’s busiest pilgrimage destination.

But following the assassination on Thomas Becket in 1170, Canterbury became a bustling hotspot for pilgrims as they came to prayer within the walls of where Becket’s blood was spilt.

Still not overjoyed despite the influx of pilgrims heading to Kent, Dr Wells suggests monks wanted to give Canterbury a further boost - by unleashing a fire which would open up new possibilities.

Speaking to The Telegraph, the University of York professor said: “What’s very interesting is the timing.

“Becket died in 1170 and was canonised in 1173, the fire took place in 1174 - not even a year following the fact that he becomes a saint.

“Once someone becomes a saint you want pilgrims through the doors.

“The way the fire starts is very interesting - a monk within the cathedral tells us that the fire started in some timber framed houses around the cathedral and the flames blew over.

“It’s just a little bit too perfect timing because as a result they build this magnificent new shrine for St Thomas Becket, these beautiful windows depicting St Thomas Becket during his life.

“So it’s a little bit too perfect, the fact they can build this magnificent new structure after he was canonised, - so was it arson or a coincidence?

“I believe it could be arson.”