A structural survey is carried out on cathedral stonework every five years

The painstaking examination of the stonework on the Bell Harry tower is done on ropes to avoid spending tens of thousands of pounds on scaffolding.

Any problems are photographed and checked for soundness and then removed if necessary.

The cathedral said it only expected to find minor wear and tear.

The Bell Harry Tower was formerly known as the Angel Steeple Bell Harry was originally hung by Prior Henry (Harry) Eastry - prior from 1285 to 1331. The first Bell Harry was used as a "calling bell" to services at the cathedral As a "passing bell" it could be tolled only on the death of a Sovereign or an Archbishop.

Spokesman Christopher Robinson said: "We know it's not falling down.

"We expect minor wear, pointing that needs renewing, various bits of stonework that may have decayed, but hopefully nothing serious."

Two stonemasons have been carrying out the checks at the cathedral, which spends �500,000 on general restoration each year.

Stone conservator Joe Picalli said: "We rig up ropes from the top of the tower using various bits of adapted climbing material and abseil down the side of the building.

"We stop where we see a problem, photograph it, check it for soundness, make sure it is not imminently going to come off and if it is, we remove it."

He said having a head for heights did not prevent moments of fear.

"If you don't get scared, then it's time to stop," he said.

"You need to have a very healthy respect for the position you're in."