The fundamental component of a no-deal scenario would be the loss of passporting rights and risking a division in portfolio across different jurisdictions and laws.
Just as the British army has Operation Yellowhammer which will come into effect in the event of a 'no deal' Brexit, bankers have their 'B-List'. This is a list of traders on standby to be deployed to other E.U. countries if passporting ends in the event of a no deal on 29th March.