LONDON — Britain’s efforts to craft a looser, more detached relationship with the European Union gathered pace Monday when the government said it planned to opt out of more than 130 justice and police measures to which it had once agreed.

The move, which was welcomed by British critics of the European Union, represents a significant turnaround for a country that, until recently, pressed hard for closer police cooperation across the Continent.

Britain in fact still wants to continue in some of the estimated 133 measures but, under an agreement it struck some years ago, has first to choose whether it accepts all of them or none. It can then discuss with European allies whether it can opt back in to specific areas.

Theresa May, the home secretary, said in Parliament on Monday that the “government’s current thinking” is that it will opt out, then negotiate to rejoin those measures it deems to be in its national interest.