It has long been argued that the extinction of the dinosaurs 65m years ago was caused by a massive asteroid strike.

But scientists have wondered why dinosaurs, which had previously been relatively puny, began to develop into giants such as Tyrannosaurus rex about 200m years ago.

One theory is that increases in carbon dioxide in the atmosphere led to bigger plants, which encouraged the development of bigger herbivores and then a growth in the size of predators.

Other scientists claim an impact by a meteor may account for the relative suddenness of the change.

"There was a relatively sudden increase in the size of dinosaurs around the time we have dated this impact," said Michael Simms, curator of paleontology at the Ulster Museum in Belfast who led the research. "This impact may well have been a factor in the changes that were going on."

Simms's team found evidence of the shock probably caused by a meteorite, which may have been up to two miles wide and hit at 18,000mph, in data from boreholes and rock formations covering 100,000 square miles.

They have not found the crater itself, but they believe the meteor may have hit what is now St George's Channel, between Pembrokeshire and the Irish coast. Much of western Britain and Ireland was under water at the time.

The crater may have been more than 30 miles wide but would now be deeply buried beneath the sea floor.

In the research, published in an academic journal, Simms looked for signs of impact rippling out from the crater in sediment that would have been affected by the shockwave. He analysed rock and borehole data and found the same unique pattern at every site he looked at, from Northern Ireland to Yorkshire and Dorset.

Paul Barrett, a paleontologist at the Natural History Museum in London, said Simms's theory was "an interesting idea".

"This is the first geological suggestion that there was an impact at this time. What we really want to back this up is a crater of the right age."

Ms Blanca Huertas, a curator at the Natural History Museum in London, said: "The description of a new bird is a rare event in modern times."

The bird, which has the Latin name Atlapetes latinuchus yariguierum, differs from its closest relatives by having a black back and no white markings on its wings.

Thomas Donegan, from the Colombian bird conservation organisation Fundacion ProAves, said: "Before we began this study, no-one knew what species lived in the Yariguies mountains and whether they needed protecting.

"Now, we are beginning to describe new taxa (types) and a national park was established in the region. It is surprising that this new brush finch and the forests of the Yariguies mountains could remain unstudied, undescribed and unprotected for so long."

Two birds were caught by the team, one of which was used to provide a DNA sample and photographs before being released unharmed. This is the first time a live specimen has been used for a description of a new bird species.

Ms Huertas said more discoveries would be made public later. "This is just the first of several new species that we will be describing from the Yariguies mountains," she said.

"In my own specialist group, butterflies, we have found several new taxa that will be described soon."

The find was announced by Conservation International which helped to fund the expedition.

Public places include stations, museums, government offices and shops but not in the streets or private places such as houses or hotel rooms.

Villepin added the state would take charge of one-third of the costs of anti-smoking treatments, such as a patch.

"That would represent the first month of treatment," he said.

In a report presented on Wednesday, several parliamentarians called for a total ban from September 1, 2007 at the latest, without exception. But a smoking ban will cause problems for the many tobacco shops in France.

Villepin declined to comment on the impact it would have on government tax revenues, saying that public health considerations outweighed any such fiscal impact.

In the report, the parliamentarians said that each year between 2,500 and 5,800 people died of the consequences of passive smoking -- inhaling the smoke of smokers. Some 66,000 smokers die each year.

Polls regularly show that a majority of French people support a ban on smoking in public places.

Weakened by a battle with trade unions and students over a controversial youth jobs contract, the government backed away in April from a ban on smoking in bars and restaurants to avoid a clash with France's many smokers and tobacconists.

Ireland imposed the world's first nationwide public smoking ban in 2004. Italy, Sweden, Scotland, Norway and Spain have followed suit to varying degrees.

Belgium, Britain, Northern Ireland and Portugal are expected to put new tighter rules in place next year.