The watchdog appointed to ensure the City’s reputation is kept squeaky clean has been forced to take action closer to home after its £60 million HQ was reduced to “shameful” squalor.

The Financial Conduct Authority’s chief operating officer Georgina Philippou said she was “appalled about the incidents of bad behaviour towards our building and colleagues”, in a letter to staff posted on the body’s intranet and seen by the Standard.

She said she was “ashamed” of the behaviour of a “minority of colleagues” as she detailed misdemeanours, including “leaving cutlery and crockery in the kitchen areas, overflowing bins, stealing plants and charging cables from desks, catering and security teams being subject to verbal abuse, colleagues defecating on the floor in toilet cubicles on a particular floor, urinating on the floor in the men’s toilets and leaving alcohol bottles in sanitary bins”.

The FCA moved into the headquarters in Stratford, on the edge of the Queen Elizabeth Olympic Park, 18 months ago. The offices house nearly 4,000 staff while many roles in cleaning, security and catering are outsourced.

Ms Philippou wrote: “You may have heard about some of these behaviours already and I’m sure others will come as a shock.

“I did think long and hard about whether to disclose all these behaviours because they are so distasteful and shameful but keeping quiet has not got us far in terms of changing behaviours. This kind of behaviour is unacceptable and will not be tolerated here.”

The FCA, an independent body funded by industry fees, is in charge of policing the UK’s financial sector and doling out fines to companies who break its strict regulations.

It is led by Andrew Bailey who has been tipped as a potential successor to Bank of England governor Mark Carney but has faced criticism of the body’s response to a number of consumer finance scandals.

The watchdog also faced anger over corporate largesse last year when the Standard revealed it had sent hundreds of staff on an away day to learn African drumming.

It is not the first time the move east to Endeavour Square has been the cause of problems for the FCA. At the time, an internal consultation highlighted staff concerns about safety in the area compared with long-term home Canary Wharf, including worries about “knife crime and gangs”.

An FCA spokeswoman told the Standard: “We have a duty as an employer to highlight this sort of behaviour and our senior management are clear it is simply unacceptable.

“Judging from the feedback we have received on the article, our staff agree.”