London Finance firms are preparing for the worst, but hoping for the best when it comes to Brexit. As they don’t know what the worst-case scenario is.

Though most finance firms agree that jobs will have to move in a worst case scenario – plans submitted by banks to the UK regulator show institutions have different ideas of what the worst outcome from Brexit could be.

Whatever the worst outcome is, it will require an absurd amount of capital to implement contingency plans post-Brexit, across the Britain’s financial landscape. Business leaders have repeatedly called for more clarity from the government over what Brexit will look like, warning that uncertainty will force many to relocate jobs out of the UK.

The AFME (Association of Financial Markets in Europe) estimated in June that a ‘hard’ Brexit could cost UK banks up to €15 billion (£13.1 billion) and add an estimated €40 billion (£35 billion to tier one capital requirements.

Firms operating across both the EU and UK post-Brexit have many regulatory options — a branch could be converted to a subsidiary or a headquarters moved to a new location, for example — which creates a headache for regulators and firms alike.

Banks that are planning a comprehensive division of work between offices in London and the EU need to transplant and split up their ecosystem established over the years. That means IT infrastructure, knowledge, process, people, and a lot of other things.