Pro-fox hunting protesters who burnt a slogan into a hillside ahead of a vote in the Commons have been described as irresponsible by conservationists.
The wildlife site could take years to recover from the burnt slogan
Supporters burnt the words "No Ban" into the grass near the Long Man of Wilmington in East Sussex.
The chalk grassland around the historic carving is designated a Site of Special Scientific Interest (SSSI).
The Sussex Downs Conservation Board and English Nature expressed their concern at the damage caused to the site.
There are up to 50 different species of plant per square metre around the area of the Long Man of Wilmington, which is one of the largest carved figures in the world.
MPs voted to ban hunting with dogs on Wednesday amid mass demonstrations in Parliament Square and despite the House of Commons being interrupted by protesters.
But it is feared the hillside could take years to recover from the burnt slogan.
Chris Edwards, team manager for English Nature's Sussex and Surrey team, said: "Whilst we recognise some people's desire to campaign against the ban on hunting, it is a pity that those concerned with the maintenance of countryside pursuits don't show a similar concern for the maintenance of our national wildlife heritage.
"This irresponsible action is not going to build public support."