The number of European workers in the City has hit its highest level on record.
Data from the Office for National Statistics, published by the City of London Corporation, shows nearly a fifth (18 per cent) of the City's workers came from the European Economic Area (EEA) in 2016, the highest ever recorded.
The City of London requested the data to inform its response to the government's consultation on immigration.
The data shows the proportion of EEA workers in the Square Mile has more than doubled in the 10 years to 2016. Europeans made up just eight per cent of the workforce in 2006.
Catherine McGuinness, policy chairman at the City of London Corporation, said: "This data crystallises the importance of European workers to the UK's biggest financial centre, and the need for a clear post-Brexit immigration policy.
"Many Europeans are in limbo over their future status here, and firms are unclear as to who they can employ, which is having repercussions on decision-making across the continent."
The Migration Advisory Committee is currently collecting responses for its review of immigration, and is expected to report the outcome in September.