Photo Credit: Just Stop Oil.
Met officers intercepted two groups, close to the perimeter fence of the airport, last July.
The protesters were found to be in possession of angle grinders and glue.
If they had been successful, the Met says the group would have had to cross one of the airport’s runways.
One other person was acquitted today while another had already admitted the offence.
Chief Superintendent Ian Howells, from the Met’s Aviation Policing Command, said:
“Last year, Just Stop Oil threatened a summer of disruption and the Met worked with police forces across the country to make sure this didn’t happen and that no members of the public were put at risk as a result of their activity.
“The reckless actions of this particular group would have not only put their own lives and the lives of others in danger, but caused havoc at Heathrow airport, bringing flights to a standstill.
“There is a clear distinction between peaceful protest and the criminal activity that this group sought to carry out.
“This kind of action will not be tolerated and the Met will continue to work with all our partners to protect the public, prevent disruption to Londoners and those visiting our city and bring offenders to justice.
“Today’s result is a clear example of this, and a reminder to anyone tempted to carry out similar actions that they will face the full force of the law.”