Both those who want the UK to leave the European Union and those who want it to stay are having a dash for cash. And the rattling of collection tins is particularly loud in the City and Canary Wharf – and Mayfair.

It has been widely reported that hedge fund millionaires are pouring their money into the Brexit campaign as they seek to escape burdensome EU regulations. But the picture that emerges from dozens of conversations - some with people who have declined to be quoted - is much more nuanced.