Residents of a seaside town branded a metric blackspot rubbed their eyes in disbelief today.

More than 160 road and pavement signs in Hastings have been secretly changed from metric to imperial measurements.

Signs which previously showed kilometres or metres now give the same information in feet, yards and miles.

The tactic was devised by a group calling itself Active Resistance to Metrication, or ARM, and Hastings represents its biggest success so far.

Members altered more than 100 signs in a single daylight swoop, the second such operation in the town, and have promised to return to finish the job.

Wearing yellow fluorescent jackets, they scaled ladders and altered signs without sparking any interest from police or the local authority.

ARM secretary, Tony Bennett, 54, said all road signs should be in imperial measurements under British law.

He said: "Many local authorities are either ignorant of the law or deliberately flouting it and we have taken it upon ourselves to put them straight.

"We would class Hastings as a metric blackspot with all sorts of different signs."

One such example, in Warrior Square, St Leonards, was a cast iron finger-pointer showing the distance to Rock-a-Nore, in the Old Town, as 3180 metres. The sign read two miles following the intervention of ARM.

Mr Bennett, a market researcher from Harlow, Essex, said: "That just shows how stupid it is to try to import alien measurements.

"It is in everyone's interests to have one clear system which everyone understands. We have got professional lettering which we use to put in nice English measurements."

ARM, which has about 12 core members and another 70 supporters across England, was founded last June following publicity about "metric martyrs", shopkeepers prosecuted for selling by the pound.