Pigeons in Trafalgar Square are dying from hunger, say government scientists who have conducted post mortems.

Campaigners blame Mayor Ken Livingstone and Westminster council for banning feeding of the birds - a popular tourist pastime that used to provide a supply of food. Since September, feeding has been outlawed in the whole square.

Five pigeon corpses were sent by the Pigeon Action Group to the Veterinary Laboratories Agency in Suffolk in October.

Going hungry: pigeons found dead in Trafalgar Square had empty stomachs

Agency scientists, who also work for the Department of the Environment, found all five had empty stomachs and protruding bones.

The Evening Standard has seen the autopsy reports which confirmed none had died from diseases. Cornelia Bidewell, one of the lab's vets, said: "All were found to be in poor bodily condition and although in some there was evidence of recent feeding, the gizzard of all birds was empty."

Julia Fletcher of the Pigeon Action Group said: "You shouldn't be able to feel the keel bone, which is under the bird.

"It should be covered with podgy flesh but with all five the bones were sticking out.

"The Mayor has been glibly reporting that his programme is 'working well' and the birds 'have left and gone elsewhere'.

"The horrific truth is that over 2,000 of these innocent, tame creatures have been subjected to a long, agonising death by starvation and brutality, spurred on by the Mayor labelling them 'rats with wings'."

Anyone caught feeding pigeons in the square can be fined up to ยฃ500, though Westminster council said it did not prosecute tourists.

Ms Fletcher said the birds did not look for food elsewhere because of their homing instinct.

A spokesman for the Greater London Authority said: "The GLA measures to reduce the feral pigeon population in Trafalgar Square and make the square more pleasant and hygienic for public use have been done in a humane way. It considers that it has at all times acted reasonably and fairly."