A cry is going out for the public to help set a new world record. No qualifications are required: All that's needed are a pair of lungs and a willing attitude and you could help Dorset gain a place in the Guinness Book of Records.

An attempt to create the largest town cry ever will take place during the Dorset County Show tomorrow. Hosting the event will be the nation's champion town crier, Dorchester's own Alistair Chisholm.

He explains: "We attempted the challenge two years ago at the Show but unfortunately the rain kept the crowds away and we could only muster up 147 people.

"Officials at Guinness stipulate that we need at least 200 participants, so fingers crossed we'll be successful this year."

The 62-year-old, who has been crying for 11 years, has won the national title four times and last year was also voted the British champion.

"It's a funny old business," he laughs. "I call it an extreme sport. It's fun, colourful, respects tradition and fits in with our national characteristic of eccentricity."

While the recognisable clothing of frilly shirt, breeches and tricorn hat are 18th-century in style, town criers were around many centuries beforehand.

Prior to the internet or even the printed word, a loud clear voice would be the main medium for mass communication, especially as many people couldn't read or write. Town criers were appointed by the civil authorities, often the mayor, to keep the citizens up to date with newsworthy items.

"We were the original newsreaders," says Alistair. Royal proclamations, local bylaws, market days, adverts, and other matters of importance were all announced by a bellman or crier throughout the centuries.

"In fact I could dress up as a soldier and be a Roman town crier. There's certainly enough history here."

One theory on the standard costume is that communications in the 18th century were getting a lot better, so the role of the town crier was more formalised.

Certainly the costume has helped Alistair in his role as a local tour guide. "In civilian clothes you sometimes only attract two-and-a-half people and a dog, whereas wearing costume attracts more."

Modern town criers are also a colourful presence at civic ceremonies and charity functions.

"It's not a full-time job. But then people wouldn't want to be shouted at all day! And it's important not to take yourself too seriously."

The Dorset County Show will also see 10 of Dorset's other town criers competing among themselves to win the Stanley Mansbridge Trophy, named after an ex town crier of Shaftesbury in his memory.

Judges will be looking for volume, sustainability, diction, inflection (including emphasis and colourful speech pattern) as well as an element of presence and confidence. Prizes also go to the best-written cry and the best dressed town crier.

Round one of the Dorset criers competition (for the 10 town criers) will take place at the town pump in Dorchester at 11.30am tomorrow while round two will take place at the Dorset County Show ground at 2pm.

Then it's your lusty-lunged chance to take part in the Largest Town Cry World Record-Breaking Attempt.

"Anyone is welcome," says Alistair. "If you can talk, you can cry. Just come along to the Countryside Arena at 4pm.

"It would be good fun to set a world record.

"We could think of it as another medal for England."

Participants in the largest town cry world record-breaking attempt will cry a Dorset ditty, written by Alistair himself.