Cuts to local policing risk a "disaster" for maintaining national security, one of the country's leading counter-terrorism officers has reportedly warned.
Neil Basu, the senior national coordinator for counter-terrorism policing, said teams tackling Islamist and neo-Nazi extremists become "divorced from the frontline" when bobbies are taken off the beat.
Two decades of work in neighbourhood policing, a vital source of intelligence on terrorist plots, is "in danger of disappearing", he told The Guardian.
"For me, that is a national security issue," he said.
Mr Basu's comments come after Metropolitan Police Commissioner Cressida Dick's warning that the UK's largest police force is under "unprecedented" pressure.
The Met is tackling an increase in crime with far fewer officers while continuing to find ways of making millions of pounds of savings, the commissioner said.
Meanwhile the mayor of London, Sadiq Khan, has called on Chancellor Philip Hammond to end a "police funding crisis" in his upcoming Budget.
The UK has experienced five terror attacks in 2017 when the threat "went absolutely stratospheric", Mr Basu said.
At least one plot was reportedly foiled hours before an attack was put into action after police received a community tip-off.
"When we don't have those people we will become so divorced from the frontline, and the frontline of communities, that will be a disaster for policing in this country," Mr Basu said.
Asked by The Guardian if it would threaten national security, he said: "Yes, because where's the intelligence coming from?"