Environmental activists invaded the site of a new incinerator before climbing a crane and chaining themselves to machinery.

Around 100 protesters, joined by a group from Brighton, staged a protest on the roof of one building in Basingstoke, Hampshire, as part of a nationwide campaign against Government plans for 43 new incinerators by 2010, including one at Newhaven.

One team of climbers set up camp in helicopter cargo nets suspended from the framework of an unfinished building during the demonstration yesterday.

The protesters joined forces with Greenpeace to halt work on building the new incinerator, which is due to open in October.

The activists fear the plant will emit large quantities of carcinogenic dioxin chemicals.

Among the protesters were Brighton residents Will Cottrell, 30, a freelance journalist, and 30-year-old secretary Penny Dawson.

They were joined by University of Brighton lecturer Julie Doyle, 29, who said: "We arrived at the site at 7am and spent a glorious day basking in the sunshine. The police are down below asking us to come down but we have an important message.

"We will be coming down tonight and getting back home to Brighton. But a few people are planning to spend a week up here.

"Incinerators emit large quantities of dioxins that cause cancer and could contaminate the food chain. We need to be talking about how to manage our waste better."

The protest was taking place on global anti-incineration day, with activists staging demonstrations in 50 countries.

Greenpeace, which is participating as a member of GAIA, the Global Anti-Incineration Alliance, said the Government recently warned a third of adults and half of the babies and toddlers in Britain absorbed more dioxins than was safe.

The Government said it was keen to boost council recycling to try to ease the pressure on landfill dumps, which are mostly used to take household waste.