A hard Brexit would pose a risk to public safety, police leaders have warned in a leaked letter.

Police and crime commissioners called on Sajid Javid, the home secretary, to draft contingency plans for a “no-deal” Brexit immediately.

They said that police forces would face “a significant loss of operational capacity”, instantly losing vital access to cross-border investigative powers and databases.

Sterling fell to an 11-month low amid growing fears of Britain leaving the EU without a negotiated settlement.

Under such a scenario, Brussels has said that it plans to “switch off” UK access to databases that allow European police forces to share information on suspects and missing persons. Police could also lose access to the EU criminal records database.

The letter from the