The High Court will decide today if thousands of badgers can lawfully be killed in a cull in the West of England this autumn.
The Badger Trust is appealing after losing its Judicial Review of the Government's controversial plans in July for a pilot cull.
The Department for Environment, Food and Rural Affairs (Defra) hopes badger control will reduce bovine tuberculosis (TB) in cattle.
TB is the biggest challenge facing the cattle farming industry today, according to Defra.
In 2011, 26,000 cattle were prematurely slaughtered as a result of the highly infectious disease.
It costs the taxpayer £100m a year in testing, inspecting and compensating farmers.
James Small, who advocates a cull, owns a large farm on the Mendips in Somerset - in one of the worst affected parts of the country.
He is chairman of the National Farmers Union for the county and says the problem urgently "needs addressing now".
He had his farm shutdown for the first nine months of this year after the disease was found in his livestock but he said he was "lucky" as only two cattle had to be slaughtered.
But his neighbour had his "life work eradicated in one test" as he lost 60% of his herd.
If the pilot goes ahead, then farmers and landowners will be issued licences to shoot badgers in West Somerset and West Gloucestershire from September 2012.
The aim is to reduce the badger population by 70% and then to maintain it at 30% for the four-year duration of the pilot.
But the Badger Trust objects to the cull, pointing out that there is no scientific consensus to prove it will significantly reduce the incidence of bovine TB.
During the first hearing at the High Court, the Government accepted that a landmark, decade-long trial, showed that culling caused social disruption among the species and that fleeing badgers can actually spread TB to new areas.
Jack Reedy from the trust told Sky News: "Forty years of science has shown if you kill badgers there is a serious risk you will make the situation worse, and that killing the badgers will make no meaningful contribution to the eradication of the disease."
According to Natural England, the Government agency overseeing the licensing process, if the policy is later fully rolled out, it could result in 130,000 badgers being killed in up to 40 hotspots.
Brian May, guitarist in the rock band Queen, will also add his voice to the Stop The Cull campaign at a rally in Bristol today.
He says it is not a question of "saving badgers versus saving cows", but rather "sensibly trying to eradicate the disease".
He added: "Even if you killed every single badger in this country you would still have bovine TB. It is a cattle disease. Badgers became infected because of defects in farming methods. So we must stop this planned bloodbath."
May is advocating vaccination as a more humane alternative.
This has already been introduced in Wales following legal challenges to a cull by the Badger Trust.
Vaccination programmes are also being trialled in Devon by the National Trust, in Gloucestershire by the Wildlife Trust and in Somerset by the Somerset Badger Group.