The protesters say they will stay on the bridge for a month

The four men, who are calling for equal access rights for fathers, scaled the gantry on the Tamar Bridge on Friday. Police were alerted at about 1340 BST.

The protesters say they are prepared to stay there for a month to raise awareness of what they see as the injustice of the family courts.

The protest coincides with the end of a similar demonstration in Exeter where a man stayed for three days on the top of a 120 feet (36 metre) crane on behalf of the organisation Fathers 4 Justice.

Jolly Stanesby climbed the crane at the site of Exeter's new Crown Court at about 0700 BST on Wednesday. He came down on Friday afternoon.

He was questioned by police and then released.

Police officers originally stopped the traffic flow on the Tamar Bridge to attempt to negotiate with the four men who had chained themselves to the structure.

Sergeant Oliver Taylor from Devon and Cornwall Police said: "At this stage, we wish to engage in dialogue with the males concerned and see if we can resolve this through negotiation."