Two fathers' rights protestors were arrested today after they tried to get on to the runway at Heathrow airport.
The pair, who made the attempt shortly after 10am, are members of a Fathers 4 Justice splinter group.
They allegedly tried to cut through a fence but were stopped before they managed to get through.
The airport's operator, BAA, said the men had been quickly apprehended and arrested and were in police custody.
"The airport's southern runway was suspended for 14 minutes, in the interests of safety," a spokeswoman said. "There has been no substantial impact to the airport's operation.
"This was a misguided and ultimately unsuccessful attempt to disrupt the travel plans of thousands of Heathrow's passengers, and we condemn the actions of those involved unreservedly."
The retired founder of Fathers 4 Justice, Matt O'Connor, said the pair were fathers' rights protesters.
"While the original campaign disbanded in September last year, there are a myriad of splinter groups in existence," he said.
He suggested there could be further protests in the coming months as fathers sought to "take the mantle back" from anti-airport expansion activists Plane Stupid, who have staged a series of high-profile stunts.
"There is no progress at all on the family courts issue, and that's a source of massive frustration," O'Connor added.
He claimed he had warned counter-terrorism command at Scotland Yard a month ago that protesters would strike at transport targets, saying he had been visited by officers who questioned him about his and Fathers 4 Justice's activities.
The group, which campaigns for equal parental access to children and has been highly critical of the way fathers are treated in family courts, has in the past been responsible for a string of demonstrations, many involving protesters dressed up in superhero costumes.
FATHERS 4 Justice are planning a string of "militant" demos after the protest at Heathrow airport today, its founder has warned.
Two men were arrested after trying to gain unlawful access to the airfield at 10am this morning.
F4J founder Matt O'Connor said: "There are a number of splinter groups planning militant action over the coming weeks.
"I'm not linked to these groups but obviously I can't stop people calling themselves Fathers 4 Justice.
"I was visited at my home by counter terrorism police a few weeks ago and questioned about whether anything was planned.
"I told them a myriad of groups are planning direct action.
"There's a huge amount of frustration out there about the lack of reform in the family courts."
Fathers 4 Justice wants dads to be treated equally in family courts' rulings on custody disputes.
Their campaigners are famed for wearing superhero costumes during their protests and in 2004 they flour bombed Tony Blair during Prime Minister's questions in the Commons.
Today Airport operator BAA said the two campaigners at Heathrow were quickly apprehended and arrested and are now in police custody.
A spokesman said: The airport’s southern runway was suspended for 14 minutes, in the interests of safety.
"There has been no substantial impact to the airport’s operation.
This was a misguided and ultimately unsuccessful attempt to disrupt the travel plans of thousands of Heathrow’s passengers, and we condemn the actions of those involved unreservedly.