THREE men dressed as cartoon character Fred Flintstone evaded tight security and scaled Stonehenge in the latest protest by protest group Fathers 4 Justice.

They climbed the ancient monument at 9.15am today and unfurled a banner with the message "Drag the family courts out of the Stone Age."

The move follows comments by Conservative leader David Cameron, who said he feels the rise in anti-social and gangland behaviour can be partly attributed to family breakdown and absent fathers.

Matt O'Connor, the founder of Fathers 4 Justice, said: "It all went to plan at Stonehenge and although the security was beefed up the three guys managed to get up there.

"David Cameron's comments about fathers angers us because it is obvious that so many fathers do care, so it's like a case of what do we have to do to show that?

"Stonehenge is kind of the cradle of our society so there is the symbolic part of the protest with that, and we've also kept the humour in there because Fred Flintstone is the most famous Stone Age person.

"Seeing Fred Flintstone on Stonehenge will add to the experience for visitors, shall we say."

The protesters have enough supplies to stay on the stones for about three days. One, Jolly Stanesby, is a hardened veteran of various Fathers 4 Justice campaigns.

A spokesman for English Heritage said: "We are disappointed this group have chosen Stonehenge to make their protest.

"We feel this disrespects the monument and there is potential for the stones to be damaged.

"The site is open to the public as usual. There is no risk to public safety and our experts are already on site to inspect the stones when the demonstration concludes."

Fathers 4 Justice campaigners are also planning protests in Westbury and Trowbridge, using the south west of England as a springboard for a national tour of the UK leading up to a London protest march on June 16.

The group is also angry that a recent UNICEF report on children's quality of life linked absent fathers and poor family life to the reasons for the UK's bottom placing.