Members of the Royal Institute of British Architects, including a past president, have signed a letter calling for UK prime minister Boris Johnson's honorary fellowship to be taken away.

Former president of the Royal Institute of British Architect (RIBA) Angela Brady has called for Johnson to be stripped of the title, while immediate past president Ben Derbyshire said a discussion on the matter was "inevitable".

Johnson was made an Honorary Fellow of the RIBA in 2011 for making an "enormous contribution" to architecture during his eight-year tenure as the mayor of London.

As mayor he was involved with several high profile architecture and design projects, including a redesign of the London Routemaster buses by Thomas Heatherwick, the ArcelorMittal Orbit tower, London's cycle sharing scheme and the Emirates Air Line cable car.

Calls to strip the title came after the British Supreme Court found Johnson's suspension of parliament to be unlawful. The court also ruled that his advice to the Queen to prorogue parliament was unlawful.

Prime minister's behaviour breaks RIBA code

"Honesty", along with "integrity and competence" are the three key tenants of the RIBA code of professional conduct.  Johnson is not bound by the code, but RIBA members have claimed his actions has bought the institution into disrepute.

"Discussion ⁦‪@RIBA‬⁩ council next week on the appropriateness of Boris Johnson's Honorary Fellowship is inevitable," tweeted Derbyshire.

"After last night's Commons debate its clear his behaviour fails to meet the standards in our new Code of Conduct for members. Sadly this does not apply to Hon. posts."

Johnson came under fire for his language when parliament reconvened, where he dismissed an MP's fears about the language used around Brexit leading to violence as "humbug".

Letter against Johnson signed by British architects

A letter calling for the honour to be stripped from the prime minister will be presented at the next RIBA council meeting on Wednesday 2 October.

"Individual architects, the RIBA as its professional institute and the representatives of our collective professionalism subscribe to behaviour that is lawful, proper and befitting," said architect Walter Menteth, who organised the campaign.

"The standard of this behaviour is codified and maintains our professionalism distinctively from civil society, and requires that integrity, probity and non-discrimination must be upheld," he added.

"In our long history as a profession no individual has or can be seen to be above those standards."

Former RIBA Honours Committee panellist Sarah Wigglesworth, who was part of the team that awarded Johnson the membership in the first place, is one of the letter's signatories. RIBA co-vice president for students and associates Simeon Shtebunaev has also signed the letter.

Peter Barber, Charles Holland and Piers Taylor are among the signatories, along with Dezeen Awards 2019 judge and London Eye architect Julia Barfield. Dean of the Pratt Institute School of Architecture and Dezeen Day speaker Harriet Harriss has also signed the letter.

RIBA promises to remain "apolitical" in judgement

As well as the unlawful suspension of parliament, the letter notes "reported comments widely construed as denigrating to women and ethnic minorities " from the prime minister and "matters of propriety and conflict of interest" in its case for removing the honorary title.

Johnson is currently under investigation from the Greater London Authority over his failed Garden Bridge project. He has also been referred to a police watchdog over accusations of misconduct regarding favours granted to a businesswoman while he was mayor.

"We are aware of the concerns that have been raised," a spokesperson for the RIBA told Dezeen.

"As a charity and professional body, we uphold standards whilst also remaining apolitical," they added.

"There is a process for considering the revocation of any honorary award, that will apply once other constitutional reforms have been agreed by the RIBA membership and the Privy Council. Any assessment would remain confidential at least until a decision has been reached."