The CISI, a professional body for those working in the financial services sector, ran the survey for six weeks, attracting over 1,300 respondents.

The online survey, which asked: “Will your clients be better off if the UK votes to leave the European Union?” (the so-called Brexit option) showed that 70% disagreed (37% “Probably not” and 33% “Definitely not”), while 15% said their clients “Definitely” would and another 15% said their clients “Probably” would be better off.

CISI CEO Simon Culhane, Chartered FCSI said: “This survey reflects the nervousness amongst our membership about the effect on their clients’ investments, as opposed to their own personal opinion, if and when the UK leaves the EU.”

Some comments that indicate Brexit would be bad for clients included:

“While the world trend is to move towards working closer – integrating economies either through the creation of trade blocks to simplify tariffs and trades or partnerships agreements – should the UK leave the EU, it will become isolated and a much smaller economy with much less influence in the world than its current strong voice and position as part of the EU group.”

“That’s ridiculous, why should the UK leave the European Union? Coming from Canada, the UK should stay in the EU. Like we have Quebec that has wanted to separate. It’s better to be friends with people and the EU economy definitely helps the UK.”

“Investors worry about the EU’s financial stability and challenges in terms of national security. The UK has been always a great place to live and invest in and is still one of the highest visited destinations in the world, as it reflects the unique style of a great living empire. Exiting the EU will definitely be a step back for stability.”

Some comments that indicate Brexit would be good for clients:

“We have to get out of the EU – it is a failed experiment and we need to get out now. There is a lot of noise in the media about "what happens if we leave?" I am far more worried about what will happen if we stay. For one thing we will continue to waste huge amounts of clients' money implementing pointless legislation like MiFID.”

“Probably not financially in the short term, but in the long term, definitely. Ultimately, better national security is worth paying a premium for.”

"As we are international, specifically from Asia, it would be a lot better off for our clients if the UK leaves the EU."

For the last six months, the CISI has been organising a series of "Great British Breakoff?" debates across the country, focusing on the economics rather than the politics of a change in the UK's relationship with the EU, with senior speakers from across the spectrum of views.

Based in the City of London, the CISI is a global organisation with offices in financial centres such as Dublin, Singapore, Hong Kong, Manila, Dubai, Mumbai and Colombo. It has 40,000 members in 116 countries.