One man has been quietly changing the law for the past 40 years - how does he do it?

Ron Bailey has been called many things in his 40 years of political campaigning, not all of them printable.

"The UK's most successful parliamentary campaigner," by a former Friends of the Earth director.

"The most effective and relentless lobbyist that it has been my misfortune to encounter during the last two decades," according to ex-minister Sir Oliver Letwin.

"A bit of a pain in the arse at times," by Lib Dem peer (and friend) Lord Foster.

Over the years Bailey has worked for groups including the Green Party, the Community Rights Project and the Sustainable Energy Association.

In that time he estimates he has been involved in getting 16 bills into law and has had a hand in a further 25 law changes.

Surprising stats for someone who use to have a poster that read "Don't vote, it only encourages them".

In his younger days Bailey was less interested in parliamentary process, preferring direct action.

His folk-singer brother first awakened his interest in politics while being "asked to leave" grammar school for "messing about" deepened his dislike of authority.

He cut his campaigning teeth in the 1960s, joining protests against harsh homelessness laws that split up families and getting involved in the squatting movement.

Activities included occupying hostels, moving homeless families into empty houses, and battling with bailiffs.

The campaigns were infused with the revolutionary spirit of the time but underpinned by Bailey's forensic understanding of the law.

He recalls spending hours in the British Library researching property laws going back to the 14th Century, so that when challenged he was armed with the facts.

More than a decade later, Bailey began trying to change the law, rather than just reading about it. One of his early victories was a freedom of information campaign.