A 63-year-old Fathers4Justice member has begun a hunger strike in protest at being denied access to his grand-daughter.
Retired historian Chris Hawkins has not eaten since Saturday and is demanding the Government meet certain conditions before he will stop the strike.
He also plans to take part in the group's Father's Day march in London on 18 June.
But Children Need Fathers, an organisation launched in January by former Fathers4Justice member Mike Ellis, has accused the group of manipulating the vulnerability of estranged fathers to further their agenda. He said the tactics used by Fathers4Justice "tars all of us with the same irresponsible brush".
But Hawkins said: "I decided to do this 12 months ago before I was even a member, and it is entirely my decision. But I came to realise that without the support of Fathers4Justice, nobody would take a jot of notice."