London is very expensive. Banks already have significant motivation to move operations somewhere cheaper, and have been doing so when they can.
That said, whilst it may seem tempting to run to the EU, other countries have been wanting to kill off the city and take its profits for their own for a long time. In the event of a remain vote, they may simply have been emboldened to outvote the UK and do it anyway, hence the focus in Cameron's negotiations on protecting the City. He knows it is vulnerable.
The banks now face a choice. Which is more risky/expensive. Needing to go through separate EU regulatory processes and get an EU "passport" via a subsidiary. Or relocate to e.g. Paris, and have all their activity be regulated by an EU now dominated by socialist governments rather than just some of it.
That said, whilst it may seem tempting to run to the EU, other countries have been wanting to kill off the city and take its profits for their own for a long time. In the event of a remain vote, they may simply have been emboldened to outvote the UK and do it anyway, hence the focus in Cameron's negotiations on protecting the City. He knows it is vulnerable.
The banks now face a choice. Which is more risky/expensive. Needing to go through separate EU regulatory processes and get an EU "passport" via a subsidiary. Or relocate to e.g. Paris, and have all their activity be regulated by an EU now dominated by socialist governments rather than just some of it.