Jonathan Evans, a former head of MI5, has pledged his support for encrypted messaging in an interview with the BBC.

He told Radio 4’s Today Programme this morning that the technology plays a vital role in maintaining the country’s cyber security.

While acknowledging that encryption had made it difficult for spies to access messages between extremists, he added:

I’m not personally one of those who thinks we should weaken encryption because I think there is a parallel issue, which is cyber security more broadly. While understandably there is a very acute concern about counter-terrorism, it is not the only threat that we face. The way in which cyberspace is being used by criminals and by governments is a potential threat to the UK’s interests more widely. It’s very important that we should be seen and be a country in which people can operate securely – that’s important for our commercial interests as well as our security interests, so encryption in that context is very positive.

The move comes after the home secretary Amber Rudd was criticised earlier this month for saying that “real people” don’t need encryption.

In an article for the Telegraph, Rudd asked: “Who uses WhatsApp because it is end-to-end encrypted, rather than because it is an incredibly user-friendly and cheap way of staying in touch with friends and family?”

Writing for NS Tech, Open Rights Group’s Ed Johnson-Williams contended that there are several legitimate reasons why people use secure communications.

“Some people want privacy from corporations, abusive partners or employers,” he said. “Others may be worried about confidential information, sensitive medical conversations, or be working in countries with a record of human rights abuses.”

Lord Evans’ intervention comes after Robert Hannigan, the former head of GCHQ, sought in July to discourage the government from weakening encryption.

In an appearance on the Today Programme, he said the technology is “overwhelmingly a good thing”.

“I don’t advocate building in backdoors,” he said. “It’s not a good idea to weaken security for everybody in order to tackle a minority.”