A no-deal Brexit will make it harder for police to protect UK citizens as forces fall back on “slower, more bureaucratic” systems, one of the country’s most senior officers has warned.

Sara Thornton, chairman of the National Police Chiefs’ Council, spoke as plans were unveiled for a new unit that will oversee how forces use alternative systems if the UK crashes out if the EU in the spring.

She said: “The fallbacks we’re going to have to use will be slower, will be more bureaucratic and it will make it harder for us to protect UK citizens and make it harder to protect EU citizens.”

There are 40 tools that UK law enforcement may lose access to, including the European Arrest Warrant and the Schengen Information System, which was accessed 539 million times by British authorities last year alone.

Thornton told journalists in London on Tuesday that officers would need to rely on international policing tools through bodies like Interpol in the event of a sudden departure from the EU.

European Law enforcement tools would be lost in a no-deal scenario, she said, meaning huge amounts of intelligence would be inaccessible to British cops.

The prospect of a no-deal Brexit has been raised by Prime Minister Theresa May, who said that Britain would walk away from negotiations if the EU did not adopt her proposed Chequers exit plan.