The British military is under pressure to strike out honors given to the sultan of Brunei, after the Asian country made death by stoning a punishment for homosexuality.

Sultan Hassanal Bolkiah, Brunei's head of state, was made an honorary air chief marshal in the Royal Air Force and an honorary admiral in the Royal Navy by Queen Elizabeth II.

Stephen Evans, CEO of the National Secular Society, has demanded the titles be removed so the UK would not be complicit in "medieval barbarism."

A global boycott of Brunei-owned enterprises is underway, with Deutsche Bank, Virgin Australia, and the London Underground among those taking action.

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The Royal Navy and the Royal Air Force are under pressure to rescind honorary military titles bestowed upon the sultan of Brunei by Queen Elizabeth II.

Last Wednesday, Brunei made death by stoning a punishment for homosexuality, after Sultan Hassanal Bolkiah made several reforms to the country's penal code, which has been based on Sharia, Islamic law, since 2014.

Brands, celebrities, governments, and universities have barred Brunei-owned enterprises and boycotted luxury five-star hotels owned by Bolkiah.

Stephen Evans, CEO of the UK's National Secular Society, last week called for the Royal Air Force and the Royal Navy to strip Bolkiah of the honorary titles.

Evans told The Observer that "Brunei's deplorable new laws are a breach of basic human rights and contrary to the values that should define British institutions."

Bolkiah. Reuters

Read more: Here's a list of everyone who is boycotting or cutting ties with Brunei after it introduced new laws to punish homosexuality with death by stoning

"Stripping the sultan of the honours they have bestowed upon him would send out the important message that they do not wish to be in any way associated with this sort of medieval barbarism," Evans added.

The Queen and Bolkiah in Bandar Seri Begawan, Brunei's capital, on September 17, 1998. Reuters

Bolkiah was made an honorary admiral in the Royal Navy in 2001. He was also made an honorary air chief marshal in the Royal Air Force, awarded by the Queen.

The decision to award Bolkiah the honors was not made by the Queen herself, Buckingham Palace told Business Insider.

Read more: The death of Queen Elizabeth will be one of the most disruptive events in Britain in the past 70 years

"Her Majesty acted on the advice of government in relation to these honorary appointments," a spokeswoman said.

Brunei's Omar Ali Saifuddin Mosque. Shutterstock/Aleksandr Sadkov

Calls for Bolkiah to be stripped of his honorary British military titles come amid a growing backlash against Brunei.

Aberdeen University in Scotland has indicated it is considering rescinding the honorary degree it gave him in 1995. Kings College London, which gave him an honorary doctorate in 2011, made a similar suggestion.

More than 60,000 people have signed a petition demanding that Oxford University revoke an honorary degree given to Bolkiah in 1993. The university first refused to do so but is now reconsidering.

Celebrities have stoked a viral campaign to boycott nine hotels owned by the Sultan, one of the richest heads of state, worth about $20 billion. It reached a peak on Thursday when eight deleted their Twitter profiles.

Hotels owned by Brunei's sultan in London, Rome, Paris, and Los Angeles. Getty/AP/YouTube/TheDorchesterCollection

They were The Dorchester (London) — where hundreds of people protested on Saturday — as well as 45 Park Lane (London), Coworth Park (Ascot, UK), the Beverly Hills Hotel (Los Angeles), Hotel Bel-Air (Los Angeles), Le Meurice (Paris), Hotel Plaza Athénée (Paris), and Hotel Principe di Savoia (Milan).

The Hotel Eden in Rome remains on Twitter but has a protected account.