Starting at noon yesterday Mr. DeCouto will stay on top of the advertising hoarding in Jackson, Tennessee, until Saturday to raise $50,000 for homeless Americans.

And the construction expert was expecting to appear on the Good Morning America show today or tomorrow.

Last night, after seven hours on top of the hoarding he described himself as "Johnny Barnes Two'' as he waved to passing motorists.

He said: "I am close to the city centre on the interstate so there has been plenty of traffic passing by.

"A lot of people have waved back to me and truck drivers have honked their horns because they know I am up here.

"I am a little bit like Johnny Barnes waving at people passing by. It is a bit like Johnny Barnes Returns or Johnny Barnes Two.'' After a special ceremony to start the marathon, Mr. DeCouto settled down and began to take telephone pledges for cash towards the building homes for the homeless under the Habitat for Humanity scheme.

An employee of Habitat, Mr. DeCouto is spending the week on a four foot by six foot perch, only being allowed down to use the bathroom for an hour each day.

From the hoarding and speaking above the noise of traffic on his cellular phone, he said: "It is OK at the moment. It has rained a little and we are expecting thunderstorms later but it should be all right. It is pretty noisy up here but that is because I am so close to the road.'' He said it has been estimated that 200,000 motorists pass the billboard every day. He said: "People are noticing me and the advertising slogans that I have up here and I am keeping myself busy taking pledges on the phonathon.

"It will really heat up tomorrow (Monday) when the TV and radio come along to interview me. Obviously there will also be a lot more traffic passing by.'' Former Saltus student, Mr.

DeCouto, 28, has worked for "Habitat for Humanity'' in Jackson for the past three years.

Mr. DeCouto said: "Habitat is an organisation that builds homes for low income families.

"Habitat opened its Jackson office in 1986 and aims to eliminate poverty housing in Jackson. But it has built many houses across the United States, Mexico and Guatemala.'' Habitat is backed by former US President Jimmy Carter who has launched a campaign to build 30 homes a week in the Southern US.

Mr. DeCouto said his charity event is a new form of advertising for the organisation. He has a "thermometer'' to show how much money has been raised and different forms of Habitat advertising, including the slogan "No More Shacks.'' He moved from Bermuda with his parents Mr. Gerry and Mrs. Mary DeCouto to Florida and studied in the US before finding work with Habitat.