She warned there are ‘growing numbers of teenagers potentially radicalising themselves online’.
Police and courts will be given powers to deal with suspects believed to be planning mass killings, according to the Home Secretary.
Yvette Cooper said the new tools will enable the criminal justice system to “close the gap” between terror suspects, who can be jailed for life for planning attacks, and individuals not driven by a particular ideology.
Police would be given powers to apprehend them before they carry out attacks.
Ms Cooper told BBC Radio 4’s State of Terror series: “There is a gap in the law around the planning of mass attacks that can be just as serious (as terrorism) in their implications for communities, their impact, the devastation that they can cause and the seriousness of the crime.
“We will tighten legislation so that that is taken as seriously as terrorism.”
She said legislation would be similar to that which allows police to arrest terror suspects for steps taken to prepare for an attack, such as research, which is not currently available without links to an ideological cause.
“We’ve seen cases of growing numbers of teenagers potentially radicalising themselves online and seeing all kinds of extremist material online in their bedrooms,” she said.
“We have to make sure that the systems can respond while not taking our eye off the ball of the more long-standing ideological threats.”
Southport attacker Axel Rudakubana, who killed three girls at a dance class, is among the individuals who could have been covered by the legislation.
