Palestine Action to be banned after break-in at RAF Brize Norton
The incident is being also investigated by counter terror police.
The Home Secretary is preparing to ban Palestine Action following the group's vandalism of two planes at an RAF base, the PA news agency understands.
Yvette Cooper has decided to proscribe the group, making it a criminal offence to belong to or support Palestine Action.
The decision comes after the group posted footage online showing two people inside the base at RAF Brize Norton in Oxfordshire.
The clip shows one person riding an electric scooter up to an Airbus Voyager air-to-air refuelling tanker and appearing to spray paint into its jet engine.
The incident is being also investigated by counter terror police.
The Home Secretary has the power to proscribe an organisation under the Terrorism Act of 2000 if she believes it is "concerned in terrorism".
Proscription will require Ms Cooper to lay an order in Parliament, which must then be debated and approved by both MPs and peers.
Some 81 organisations have been proscribed under the 2000 Act, including Islamist terrorist groups such as Hamas and al Qaida, far-right groups such as National Action, and Russian private military company Wagner Group.
Another 14 organisations connected with Northern Ireland are also banned under previous legislation, including the IRA and UDA.
Belonging to or expressing support for a proscribed organisation, along with a number of other actions, are criminal offences carrying a maximum sentence of 14 years in prison.
Friday's incident at Brize Norton, described by the Prime Minister as "disgraceful", prompted calls for Palestine Action to be banned.
The group has staged a series of demonstrations in recent months, including spraying the London offices of Allianz Insurance with red paint over its alleged links to Israeli defence company Elbit, and vandalising Donald Trump's Turnberry golf course in South Ayrshire.
The Campaign Against Antisemitism (CAA) welcomed the news that Ms Cooper intended to proscribe the group, saying: "Nobody should be surprised that those who vandalised Jewish premises with impunity have now been emboldened to sabotage RAF jets."
CAA chief executive Gideon Falter urged the Home Secretary to proscribe the Houthi rebel group and Iran'sRevolutionary Guard Corps, adding: "This country needs to clamp down on the domestic and foreign terrorists running amok on our soil."
Former home secretary Suella Braverman said it was "absolutely the correct decision".