WhatsApp is threatened with a shut down in Britain as ministers press ahead with plans to require easier access to messages for police and MI5, the messaging app has warned.

Will Cathcart, head of WhatsApp at Meta, which also owns Facebook and Instagram, told The Telegraph he was prepared to see the app blocked for British smartphone users rather than weaken its security.

The Online Safety Bill currently making its way through Parliament, includes powers to enable law enforcement to access encrypted messages on services such as WhatsApp.

Although WhatsApp has never proactively withdrawn its service from a country, Mr Cathcart said the company would not weaken its security in response to a demand from Britain alone.

Mr Cathcart said: “The Bill provides for technology notices requiring communication providers to take away end-to-end encryption – to break it.

“The hard reality is we offer a global product. It would be a very hard decision for us to make a change where 100pc of our users lower their security.”

Will Cathcart
Head of Whatsapp Will Cathcart has said he is prepared to see the app blocked for British smartphone users rather than weaken its security
WhatsApp is used by 40 million people in the UK and around two billion worldwide. Mark Zuckerberg acquired the app in 2014 for $19bn.

End-to-end encryption means that nobody, not even law enforcement or WhatsApp itself, can see the contents of its two billion users’ private messages.

WhatsApp is banned in China, Syria and Qatar. In the UAE, users are blocked from making video calls. Iran recently moved to ban its app amid widespread anti-government protests, but WhatsApp insisted it would do everything in its “technical capacity” to continue accepting Iranian users.

Child safety campaigners have claimed this means child abusers can hide their deeds on secure messaging apps, while police services have argued it can hamper counter-terror investigations. Meta, the owner of Facebook and WhatsApp founded by Mark Zuckerberg, has faced criticism for its efforts to implement end-to-end encryption.

However, Mr Cathcart said the technology was critical to personal privacy in the age of the internet and similar to private conversations in the home.

Mr Cathcart said: “So far it has just been authoritarian countries that have banned it. We feel the best trade off is to offer a secure service for all people that do have access to it – and to accept that in some countries we are banned.”

It is the strongest signal that WhatsApp would be willing to stop its app working in the UK, rather than bow to demands to change its encryption. Ministers will have the power to force internet providers to block apps from operating in the UK if they fail to obey the Online Safety Bill’s regulations.

Meta has previously followed through on threats to withdraw from markets. It blocked all news content from Facebook in Australia in protest of laws making it pay for news. However, it returned within days after tweaks to legislation and made substantial payments to publishers.

The Online Safety Bill was reintroduced by Culture Secretary Michelle Donelan this week. The rules will give regulators powers to impose billions of pounds in fines on tech giants.

The row pits the ministers against Silicon Valley. This week, Apple said it would add additional encryption to its iCloud internet storage service for iPhones.

The Government has said the Online Safety Bill could, as a “last resort”, give telecoms regulator Ofcom the power to force private messaging apps to use “highly accurate technology to scan public and private channels for child sexual abuse material”.

A government spokesman said: “We support strong encryption but it cannot come at the expense of protecting children from exploitation. End-to-end encryption cannot be allowed to hamper efforts to catch perpetrators of the most serious crimes.

“Ofcom will have a power under the Online Safety Bill to, where necessary and proportionate, direct platforms failing to tackle child sexual abuse to take action. We remain committed to continuing to work with the tech industry to develop innovative solutions that protect public safety and privacy.”