A resident who called 999 to report the three white vans in Whelford village said it was “pure luck” that she spotted the vehicles.
Speaking to Radio 4’s Today programme the woman, who wishes to remain anonymous, said she arrived home to find the driveway and road blocked and saw a “large group of hooded and masked men”.
“When they saw me they ran ahead of me – some into the field and some towards the neighbouring village of Kempsford. I then realised that something highly unusual was taking place,” she added.
The woman told the programme she called the Ministry of Defence police at RAF Fairford but received no answer. She then rang 999 at 01:36 BST and said “within 10 minutes the village was full of armed police”.
“I believe that my 999 call foiled whatever plans they had.”
“I am absolutely staggered that it was left to me as a member of the public to see and report this,” she said.
“Someone really dropped the ball on this.”
Another resident described the moment he said he saw police apprehend the suspects.
Jeff – who did not give his surname – told the he heard “shouting outside his front door”, although he could not be sure where it came from.
He said he then looked out of his window and saw “people being held by police outside”.