OCCUPY campaigners launched a legal challenge to London Mayor Boris Johnson yesterday after his decision to fence off Parliament Square was deemed unreasonable by human-rights lawyers.

With the help of human-rights group Liberty, Occupy Democracy have applied for judicial review of the measures taken to prevent peaceful demonstrations in the square.

Social-justice campaigner George Barda said: “The repressive approach of Boris Johnson (pictured) and his henchmen has been disappointing if not surprising.

“It’s crucial that we fight back against this contempt of the basic rights that are our last defence against corrupt and unaccountable power.

“The most important thing, though, is that we resolve this situation so we can get on with what we wanted to do in the first place, which is to shine a light on the systematic corruption of the entire edifice of democracy by powerful economic interests.”

Metal fences were installed around the square in October — a few days after the start of the Occupy Democracy camp.

According to the London Authority the enclosure was

put up to protect the grass — but it soon expanded to other areas beyond the green.

Liberty lawyer Rosie Brighouse said that “the irony of preventing peaceful protest in the heart of the world’s oldest democracy can’t have escaped the mayor.

“Surely exercising democratic rights is to be celebrated, not censured, especially in an election year — Parliament Square is not his private back garden.”

The move was taken to coincide with the Occupy Democracy’s celebrations of the 750th anniversary of the Magna Carta.

Occupy Democracy will return to Parliament Square on Saturday for its third monthly two-day occupation.

This weekend the group will be supporting CND’s Wrap Up Trident demonstration, which will see Westminster encircled by a seven-mile-long peace scarf.

A group supporter said: “We are commemorating democracy day by seeking to protect our right to protest in court and by asking people to join us on Saturday in front of Parliament to take direct action and to build the movement for democracy free from corporate control.”