More than 100,000 people have signed an online petition opposing the cull of badgers planned for Gloucestershire and Somerset.
The petition was launched last week by Queen guitarist Brian May as part of the 'team badger' campaign. It could mean the decision is referred back to parliament for further debate.
A licence has been granted for a cull to begin in Gloucestershire, while a second application for West Somerset is still being considered. The government hopes the pilot culls will pave the way for more widespread culling.
As many as 3,000 badgers could be shot during the first cull, which farmers say is necessary because the wild animal spreads the disease to livestock.
At the launch of the Team Badger billboard in London, May said he became involved with the issue "even before this government was in office, because it was apparent to many of us what was going to happen if David Cameron was given power - that animals, wild animals, were going to become completely unimportant, unrepresented."
The musician and campaigner said every badger was a "thinking, feeling being".
A long-term study found that culling of badgers over a number of years on a large scale could reduce the incidence of TB in cattle herds by 16%. But May said the cull was "scientifically, practically and ethically indefensible and it is against the wishes of the majority of people of this country".
He wants the cull to be abandoned in favour of vaccination, which he believes is the only long-term hope for eradicating TB in cattle.