Counter-terror police have arrested four people after military planes were sprayed with paint during a break-in at RAF Brize Norton that was claimed by a pro-Palestinian group.
Footage posted online last Friday by Palestine Action showed two people inside the Oxfordshire airbase in darkness, with one riding on a scooter up to an Airbus Voyager and spraying paint into its jet engine.
South East counter terrorism police have now arrested a 29-year-old woman of no fixed abode and two men, aged 36 and 24, both from London, on terror charges.
A 41-year-old woman, of no fixed abode, was arrested on suspicion of assisting an offender.
The suspects aged 24, 29 and 36 are suspected of "the commission, preparation or instigation of acts of terrorism, contrary to Section 41 of the Terrorism Act 2000", police said.
The arrests took place in Newbury, Berkshire, and all suspects remain in custody.
The government has said it will proscribe Palestine Action following the incident at Brize Norton, making it illegal to be a member or invite support for the group.
Home Secretary Yvette Cooper said a draft proscription order would be laid before Parliament on 30 June.
South East counter-terror police gave no further details about the individuals it had arrested, nor their suspected link to the incident.
Palestine Action said its activists were able to evade security and claimed they had put two air-to-air refuelling tankers "out of service".
The group said activists used repurposed fire extinguishers to spray the paint and caused "further damage" using crowbars.
However, Downing Street said the incident had not blocked any planned aircraft movements or stopped any operations.
The base is encircled by a large perimeter fence, with security camera and sensors in the area in addition to manned security checkpoints. Patrols around the base are also carried out from time to time.
But a defence source said these measures would not have been able to provide complete cover around the large airbase.
Defence Secretary John Healey said he was "really disturbed" by the incident and ordered a wider security review of all UK military bases.
Prime Minister Sir Keir Starmer condemned the break-in as "disgraceful", characterising it as an "act of vandalism".
RAF Brize Norton serves as the hub for UK strategic air transport and refuelling, including flights to RAF Akrotiri in Cyprus.
The air force has conducted reconnaissance flights over Gaza out of the Cyprus base, though the Ministry of Defence told the BBC that RAF Voyager aircraft had not been involved in refuelling or supporting Israeli Air Force jets.
A Palestine Action spokesperson said in a statement shortly after the break-in: "Despite publicly condemning the Israeli government, Britain continues to send military cargo, fly spy planes over Gaza and refuel US and Israeli fighter jets."
Police said the incident took place in the early hours of 20 June and that "damage was caused to two aircraft".