The UK like most Western countries is in debt. The UK is much smaller than the US and is struggling to keep tabs on the 3,500 Muslims in their country suspected of being terrorists or terrorist sympathizers, which includes about 400 ISIS fighters that have returned home. These numbers have grown in recent years at the same time as "moderate refugees" have been let in to the country.
They have actually cut back on monitoring as these numbers grow.
Potential terrorists in UK swells to 3,500 - but powers to monitor used LESS than in 2015 | UK | News | Express.co.uk
I realize that it is extremely expensive to keep close tabs on so many people, but it seems like it is a matter of life and death.