NEW YORK -- Hours after the latest terror attack hit London, British prime minister Theresa May used a speech to repeat a key party manifesto pledge in the upcoming election -- that the internet must be regulated to combat online extremism.

May said introducing the rules would "deprive the extremists of their safe spaces online," arguing that tech firms were not doing enough to remove and report content.

"We cannot allow this ideology the safe space it needs to breed. Yet, that is precisely what the internet and the big companies that provide internet-based services provide," said May.

May added that there should be no "means of communication" which "we cannot read."

The British premier has been accused of "foolish political grandstanding" and using the attack to push a political promise, days before the public is set to vote for their new lawmakers and prime minister.

Seven people were killed and dozens were injured in the vehicle and knife attack Saturday.

It's the third terrorist attack in four months -- following the Westminster Bridge attack and the suicide bombing in Manchester -- that have slipped through the surveillance net. May did confirm that five plots have been disrupted since March, an indication that intelligence agencies are at least catching some potential attacks with its vast surveillance apparatus.

But authorities have confirmed that the response to Saturday's attack was "police-led," indicating that there was no prior intelligence, suggesting the government was caught entirely by surprise.

Despite the political rhetoric, neither May nor the police have shown any evidence that the internet was involved in any way.

On one part, it gives a possible insight into why no intelligence was picked up in the first place, and yet on the other, questions remain if greater surveillance would have even helped.

Peter Neumann, a professor at King's College London, criticized May's "political" speech.

"Big social media platforms have cracked down on jihadist accounts, with result that most jihadists are now using end-to-end encrypted messenger platforms e.g. Telegram," he said in a series of tweets. "This has not solved problem, just made it different."

"Moreover, few people radicalized exclusively online. Blaming social media platforms is politically convenient but intellectually lazy," he added.

One British lawmaker said on Twitter, responding to a BBC reporter, that police and counter-terror officials are more likely to ask for greater resources and "not new laws."

Many have already taken to social media to criticize May's remarks as distasteful -- accusing her of using tragedy to push forwards a political agenda, but it's not the first time she has been criticized for going overboard on surveillance.

During her previous tenure as home secretary, May was hellbent on pushing through new surveillance powers. After an earlier attempt to push through the so-called "Snoopers' Charter" was blocked by the government's coalition partners, she finally got those powers into law in 2015 when her government won an overall majority in parliament. The law, among other things, requires internet providers to maintain lists of browser histories for a year, and police do not require a warrant to query the database.

Even now as prime minister, she has overseen a proposal to expand those recently passed surveillance powers in an effort to gain "direct access" to phone and internet providers' systems, in part in effort to break end-to-end encryption.

That same party line was parroted by incumbent home secretary Amber Rudd -- who succeeded May -- who told ITV News that tech companies should "help work with us to limit the amount of end-to-end encryption that otherwise terrorists can use to plot their devices."

Tech firms, including Facebook and Google, have already decried the response.

One privacy watchdog, the Open Rights Group, criticized the government's approach, saying in a blog post that it was "disappointing that in the aftermath of this attack, the Government's response appears to focus on the regulation of the Internet and encryption."

"While governments and companies should take sensible measures to stop abuse, attempts to control the Internet is not the simple solution that Theresa May is claiming," said Jim Killock, executive director of the group.

Given May's pro-surveillance and anti-encryption track record, should the Conservatives succeed in Thursday's election, the battle between government, tech giants, and privacy advocates is likely to endure.

ZDNet's Charlie Osborne contributed.