Fry said Canadian black bears are "mercilessly killed" and their fur often ends up in the iconic headwear.

However, the Ministry of Defence said the fur is from "legal and licensed hunts" intended to manage populations and the bears "are not hunted to order".

Narrating a video for animal rights group PETA, Fry said they are killed with guns or crossbows after being lured with buckets of food.

"Bears who are shot don't always die outright," he said.

"They may flee and endure a slow, painful death from infection or blood loss - only to be found hours later after the hunters follow their bloody trail."

Fry said the skin of one bear is needed to make a single cap and the continued use of fur by the Army incentivises hunters to kill.

The caps are worn by the Grenadier Guards, the Coldstream Guards, the Scots Guards, the Irish Guards and the Welsh Guards.

They have been used for more than 200 years but are now purely ceremonial, worn during parades and by guards at places such as Buckingham Palace.

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But Fry said "tradition is never an excuse for cruelty" and that the use of real fur "brings dishonour to our country".

He wants the Ministry of Defence to switch to an artificial version that PETA says is as good as - and in some respects better - than the real fur.

"It's time to modernise this iconic symbol of Britain by switching to a fabulous faux fur that has been tested specifically to ensure its suitability for use by the King's Guard," said PETA senior campaign manager Kate Werner.

However, a Ministry of Defence spokesperson said "an alternative has yet to meet the standards required to provide an effective replacement for the bearskin ceremonial caps".