British police and environmental protesters were resuming their stand-off at London's Heathrow Airport protest camp Wednesday amid signs of growing tension.
Last night saw the closest the two sides have come to a flashpoint when up to 30 officers were blocked as they attempted to enter the site.
Organisers said the surprise move by police was repelled by more than 100 demonstrators who raced to block officers from advancing into the camp.
Timothy Lever, one of the camp's spokesmen, told reporters, "A large number of police attempted to break into the camp and they were peacefully removed by a large crowd of protesters with their hands in the air who gradually moved the police away.
"The police gave us no warning and did not say why they were coming on the site. They did it after the media left." Protesters have fiercely defended the field they are illegally occupying close to the boundary of the west London airport.
Since the camp first appeared last Sunday they have only allowed up to four officers to patrol on site to check for illegal activity.
Tensions rose between protesters and police earlier yesterday as officers attempted to photograph many of those arriving at the camp.
Protesters, who recorded the incident, said police claimed afterwards they were attempting to count the numbers of those on the site.
In a statement, Scotland Yard said, "Uniformed forward intelligence team officers patrolling the camp met with some opposition from some of the camp participants. Additional officers were then deployed in support of them.
"Police worked with the camp liaison to resolve the issue. Policing levels have now returned to the normal patrolling officers," the statement added.
Organisers estimate 550 people had joined the rain-lashed camp last night.
In a further development yesterday, protesters refused to rule out illegal activity as they began to discuss plans for a "day of action" at the airport this Sunday, but they insisted they would not resort to violence.
Police doubled their numbers at the site, with mounted officers, sniffer dogs and an ANPR (automatic number plate recognition) van working alongside vanloads of officers.
Fears were further raised when camp organisers confirmed they had sent an e-mail urging activists to bring smart clothing to blend in with ordinary workers.
The protesters are staging their action to highlight the dangers of climate changes and the dangers caused by air travel affecting the environment.