Being a freeman of the City of London used to mean strolling around with your sword unsheathed, getting as drunk as you liked and driving your sheep across London Bridge for free.

But while the first two privileges have long since lapsed, on Friday the city's freemen reasserted their sheep-driving rights before a crowd of bemused onlookers.

A flock of Romney ewes crossed the concrete bridge to the sound of drums as the financial center's lord mayor, David Lewis, led the way.

Theresa Lewis, the mayor's wife, said she hoped the stunt — being put on to raise money for charity — would boost the morale of London workers grappling with the economic crisis.

"Hopefully it is a bit for fun for business people to see, whose day may not be full of happiness at the moment," she said.

The tradition of freemen — people who enjoy civil or political liberty — stretches back to the Middle Ages, when the inhabitants of towns and cities would be granted lucrative trading rights and other privileges.

In the City of London, the small area which now makes up the British capital's financial district, those included exemptions from bridge-crossing tolls, the right to bear a naked blade and to get escorted home when intoxicated.

Murray Craig, the man now in charge of granting and managing the freedom of the city, said the privileges have "fallen into abeyance."

He said the freedoms are awarded to about 1,700 people annually. However with banks and stock markets having replaced the City of London's butchers and slaughterhouses, sheep crossings at London Bridge are extremely rare.

Some privileges apparently deserve to remain in abeyance. As for carrying an unsheathed sword in a city unnerved by a spate of stabbings, Craig advised freemen against it.

"Oh God no!" he exclaimed. "With all this knife crime, that would be terrible."