British Prime Minister Theresa May will restate her case Saturday for an unprecedented security partnership with the European Union after Brexit, warning that lives depend on it.
In a speech to the Munich Security Conference, she will acknowledge that no deal currently exists between the EU and a third country "that captures the full depth and breadth of our existing relationship".
But she will warn: "This cannot be a time when any of us allow competition between partners, rigid institutional restrictions or deep-seated ideology to inhibit our cooperation and jeopardise the security of our citizens.
"We must do whatever is most practical and pragmatic in ensuring our collective security."
Her comments come after the heads of key British, French and German spy agencies warned in a rare joint statement that intelligence sharing and cooperation must continue even after Britain leaves the EU.
Media reports suggest May will announce that Britain wants to maintain the European arrest warrant (EAW) and stay part of Europol, the EU's law enforcement agency.
However, some experts have warned that cooperation on police and security matters could be limited by Britain's refusal to accept the jurisdiction of the European Court of Justice (ECJ) after Brexit.
May has previously drawn criticism for appearing to link security -- in which Britain is a major player -- with her hopes for a new trade deal with the EU.
"There is precedent for comprehensive, strategic relationships between the EU and third countries in other fields, such as trade," she will say Saturday.
"And there is no legal or operational reason why such an agreement could not be reached in the area of internal security."