The Bank of England (BoE) warned Brussels on Tuesday to move swiftly to shield financial markets from a “cliff-edge Brexit.”

Britain is set to leave the European Union at 11 p.m. London time on Friday, 29 March 2019. The financial sector is not ready, according to the BoE. Brussels needs to step up.

In its most stern report to date, the BoE raised concerns about insurance, derivatives and data-transfer.

“In the limited time remaining, it is not possible for companies on their own to mitigate fully the risks of disruption to cross-border financial services,” the BoE warned the European Union, Reuters reports.

Attention is now primarily focused on derivative contracts worth €47 trillion in nominal value. Issued under UK law, these contracts now face legal uncertainty.

Furthermore, the insurance sector is facing similar challenges as nine (9) million insurance policyholders around Europe face similar regulatory challenges.

The European Commission responded on Tuesday that stakeholders have been informed about impending risks and encouraged to prepare for Brexit. For many firms, that means setting up subsidiaries in the EU, or relocating altogether. 15 of the UK’s biggest international banks have already announced the relocation of 6% of their London workforce, or 4,500 jobs.

The European Central Bank (ECB) warned banks they have a maximum of three years (2022) after Brexit to curtail their use of a “back-to-back” booking model, which makes it easier to keep staff and capital in the UK, The Financial Times reported on Sunday.

“Back-to-back” is the practice of trades and loans processed in the EU to be booked in London, where the capital will remain. The ECB would like to see the phasing out of the practice as and the transfer of derivative contracts in the Eurozone.

On the other side of the Channel, the UK has moved to unilaterally grand permission to EU financial firms to continue doing business in London, even in the event of a no-deal Brexit. That means EU firms will be able to operate with branches rather than subsidiaries. The EU has not responded in kind.

Thus far, the BoE and the European Central Bank (ECB) have avoided joint statements or open cooperation. The immediate challenge is that “no deal” would mean no transition period, which would require coordinated response.