The European Union has revealed a draft law to give it the power to move the lucrative euro clearing business out of London and keep it in the EU after Britain leaves the Union in 2019.
London currently processes three-quarters of the trade in this financial sector, providing thousands of jobs.
But European Commission Vice-President Valdis Dombrovskis said Brexit needed certain adjustments to our rules.
The law will decide if London will have the right to host the work post-Brexit.
London is currently the world leader for the clearing of all types of currency-denominated derivatives including the euro.