WhatsApp feels the heat over Westminster terror attack

Technology giants will this week face more pressure to allow intelligence services access to encrypted messaging in the aftermath of the Westminster attack.

Khalid Masood is known to have used WhatsApp in the moments before the attack, but encryption has hampered investigators trying to access his messages.

The company has faced a barrage of criticism - not least from Home Secretary Amber Rudd - at a time when tech firms were already under pressure over extremist content.

They have been invited to a meeting with government officials later this week.

And the giants of Silicon Valley once again find themselves in the centre of the debate over privacy and security.

:: Messaging apps and terror: Seven key questions

Ian Sherr, executive editor of tech magazine CNET (NasdaqCM: CNET - news) , said: "It is all about privacy. The concern the tech industry has is that if they allow anyone access once it is just going to snowball and suddenly the government is going to be able to pull in anything they want."

In some ways, he said, tech firms might relish the opportunity to show consumers how hard they fight to protect their data, a key selling point of what they offer.

And it is not clear what capabilities firms such as WhatsApp currently have to access data contained in communications.

But, as with Apple (NasdaqGS: AAPL - news) 's clash with the FBI over the San Bernardino gunman's iPhone, it raises some uncomfortable questions.

"They said 'we can't build this programme and then pretend like it never happened'," said Mr Sherr. "So they don't want to make that opening for anybody."

It is the focus of much discussion on the streets of WhatsApp's hometown of Mountain View in Silicon Valley.

It was founded by Jan Koum and Brian Acton in 2009, using the Red Rock Coffee Company as a makeshift office.

Today the company, bought by Facebook (NasdaqGS: FB - news) for $19bn (£15bn) in 2014, occupies a stylish new office complex a hundred yards away.

No signs confirm that WhatsApp owns the headquarters - and when Sky News paid a visit to the building, security guards refused to confirm which company was based there.

Outside Red Rock, programmer John Voorhees told Sky News: "If you're looking for people who want to do harm to us you need to consider better ways of getting information that are not just broad collections of data.

"You need to use connections within communities and things like that. There are lots more intelligent ways to go about gathering information."

Some of Mountain View's more traditional industries have some sympathy for their neighbour.

Diana Tucker, who owns the West Valley Music store, said: "I tend to fall more on the tech side because once you open that box, that genie will not go back in."

WhatsApp says it is cooperating with law enforcement over the Westminster attack.

But it is evident that governments around the world want more than that.