Employees at Lloyd's of London are up in arms at a drinking ban during work hours that the insurer has introduced.
Lloyds warned that a breach of the ban would be considered gross misconduct leading to dismissal from work.
Founded in 1688, the insurance market acknowledged the City of London had "historically had a reputation for daytime drinking", but said the demands of the modern world meant alcohol was off the lunch menu.
The Evening Standard reported that the order had drawn the ire of staff which they vented in an online forum.
One said it made Lloyd's the "PC capital of the world", while another asked: "Will we be asked to go to bed earlier soon?"
According to an internal memo seen by the paper, the policy which applied to 800 employees of Lloyd's, but not the brokers or underwriters from other companies based at the market, aligned the firm with many of its competitors.
"The London market historically had a reputation for daytime drinking but that has been changing and Lloyd's has a duty to be a responsible employer, and provide a healthy working environment.
"A zero limit is therefore simpler, more consistent and in line with the modern, global and high performance culture that we want to embrace."
A Lloyd's spokesman told the Standard, "Our employee guidance was recently updated and provided clarification on the Corporation's position on drinking alcohol during the working day, which is prohibited."
The ban was introduced after "roughly half" of grievance and disciplinary procedures in the past year were reportedly found to relate to the misuse of alcohol.