On Monday, May addressed an audience at the Institute of Mechanical Engineers in central London with a speech partly devoted to the United Kingdom's membership of the European Union and possible risks for the country in the event of Brexit.
"If we were not members of the European Union, of course we would still… be part of the Five Eyes, the closest international intelligence-sharing arrangement in the world. We would still have our first-rate security and intelligence agencies… But that does not mean we would be as safe as if we remain… So my judgement, as Home Secretary, is that remaining a member of the European Union means we will be more secure from crime and terrorism," May said.
According to the home secretary, outside the bloc, London would not be able to avail of the European Arrest Warrant system, which facilitates the extradition of thousands of criminals, including terror suspects, between EU member states each year.
"… without the kind of institutional framework offered by the European Union, a complex agreement like this could not have been struck across the whole continent, because bilateral deals between every single member state would have been impossible to reach," May added.
According to May, EU membership serves UK economic and trade interests.
Retaining certain security components after leaving the European Union falls short of the intelligence-sharing benefits the United Kingdom enjoys as a member of the 28-member bloc, May said.
"If we were not members of the European Union, of course we would still have our relationship with America. We would still be part of the Five eyes [alliance], the closest international intelligence-sharing arrangement in the world," May outlined the pro-Leave arguments.
The United Kingdom’s "first-rate" security and intelligence agencies, as well as intelligence sharing on terrorism and crime with EU allies would also stay unchanged should the British voters side with the Leave camp, she added.
"But that does not mean we would be as safe as if we remain," the home secretary stressed in a speech billed as her first on the EU referendum.
"So my judgment, as Home Secretary, is that remaining a member of the European Union means we will be more secure from crime and terrorism," she concluded.
UK citizens are set to vote on June 23 in a referendum on the country's EU membership, after Prime Minister David Cameron and the leaders of the other 27 European Union member states reached a deal in February to grant the United Kingdom a special status within the bloc.