Badger culling has started for a second year in the South West, prompting renewed calls from opponents for the controversial policy to be abandoned.

The Government said culling of the wild animals had resumed in two four-year pilot schemes in Gloucestershire and Somerset as part of efforts to tackle bovine tuberculosis (TB) in cattle.

Ministers and farmers insist culling is necessary to address TB in livestock, which saw more than 26,000 cattle slaughtered in England last year and multimillion-pound losses.

But opponents say culling is inhumane and ineffective, and alternatives such as vaccination should be pursued. They are also concerned that monitoring of the pilot culls by a panel of independent experts has not been resumed this year.

An independent report by an expert panel into the first year of culls found that "controlled shooting" - of free-running badgers - could not deliver the level of culling needed to bring about a reduction in TB in cattle and was not humane.

Environment Secretary Elizabeth Truss said: "We are pursuing a comprehensive strategy, supported by leading vets, which includes cattle movement controls, vaccinating badgers in edge areas and culling badgers where the disease is rife.

"This is vital for the future of our beef and dairy industries, and our nation's food security.

"At present we have the highest rates of bovine TB in Europe. Doing nothing is not an option and that is why we are taking a responsible approach to dealing with bovine TB."

Last year the pilots failed to kill the 70% of the badger population thought to be needed to make the cull effective in reducing TB in cattle herds in the area, despite a five-week and three-day extension in Gloucestershire and a three-week extension in Somerset.

In Somerset, 940 badgers, 65% of the population, were killed and in Gloucestershire the figure was less than 40%, with 921 killed.

This year the companies carrying out the culls will have to kill a minimum of 316 badgers in Somerset and 615 badgers in Gloucestershire, with a maximum permitted of 785 in Somerset and 1,091 in Gloucestershire, in a six-week period.

Meurig Raymond, president of the National Farmers' Union, wrote to members to inform them the second year of culling has started.

Travelling round the country, he said he has seen first-hand the human misery the disease caused for livestock owners and their businesses, and said his own farm was currently under TB restrictions.

"No one would choose to kill badgers if there was an effective alternative in areas where TB is rife. But if we're ever going to get on top of bovine TB in areas where the disease is endemic, there is no other choice," he wrote.

"The Chief Vet has said culling over a four-year period in both pilot areas will have an impact on disease control.

"I am confident that these pilot culls will help deliver a reduction in bovine TB in cattle and it is vital that they are allowed to be successfully completed so they can deliver the maximum benefits."

Mr Raymond also said that badger vaccination "could have a role to play" in areas that are clear of bovine TB to stop the disease spreading any further.

Anti-cull campaigners said badger culling would not tackle the problem.

Dominic Dyer, of the Badger Trust and Care for the Wild, said: "These culls are ill-conceived and incompetently managed, and will contribute nothing to reducing bovine TB in cattle.

"Here we have a Government and the National Farmers' Union pushing ahead with a policy simply because they don't have the guts to admit that it is wrong, and a complete and utter disaster for the farming industry, taxpayer and the protection of our native wildlife."

Mr Dyer said campaigners were likely to take the High Court decision to reject a judicial review of the need for independent monitoring of the cull operators to the Court of Appeal.

Queen guitarist Brian May called on this year's culls to be cancelled.

"It's almost beyond belief that the Government is blundering ahead with a second year of inept and barbaric badger killing," he said.

"TB in cattle in England is currently at its lowest level in 10 years, the drop being predictably the result of improved husbandry in cattle.

"So this is a most inappropriate moment for Cameron to be wasting taxpayers' money persecuting our wildlife against the advice of every independent scientist in the field."

Mark Jones, a vet and executive director for Humane Society International/UK, said: " Independent scientific advice that killing badgers is a waste of time has been eschewed, independent oversight of the culls abandoned, kill targets have been set without an accurate idea of actual badger numbers, and farmers continue to be misled into thinking that killing these animals will help solve bovine TB when all the evidence points to the contrary.

"While Wales continues to get a grip on this disease without harming a single badger, here in England ministers are set on appeasing those who would rather shoot innocent animals than focus on cattle-based measures that worked back in the 1950s and 1960s and are working so well in Wales today."

Paul Wilkinson, head of living landscape at The Wildlife Trusts, said vaccination of cattle was the long-term solution to bovine TB.

"It is hugely frustrating that the culling continues," he said.

"We work very closely with the farming community, as well as being significant farmers and landowners in our own right, and are very conscious of the hardship that bovine TB causes.

"Culling badgers is not the answer. It won't significantly reduce disease prevalence in cattle and could even make the situation worse, due to the perturbation effect where the disease is spread by badgers moving between setts post-cull.

"It is vital that we find the right mechanisms to control this disease and the emphasis of all our efforts should be to find an effective, long-term solution.

"We firmly believe that vaccination offers the most effective, long-term and sustainable approach to bovine TB in badgers, and there is a strong scientific evidence base supporting this view."

Shadow environment secretary Maria Eagle said: "Last year an independent expert panel concluded that these badger culls were 'ineffective' and 'inhumane', and more recently they have been described as an 'epic failure' by the chief scientific adviser to Natural England.

"But instead of abandoning these appalling culls, the Government have chosen to press ahead without any further independent expert monitoring.

"Labour has consistently said that to get Bovine TB under control, we need to bring in stricter cattle measures and prioritise badger and cattle vaccinations, but these culls are not the answer."

Last week the Government announced a scheme to vaccinate badgers next to the two cull areas to create a "buffer zone".

Under the scheme - which will target counties in a strip down the middle of England such as Cheshire, Oxfordshire and Hampshire - a package of support will be available, including funding of up to 50% of the long-term costs for vaccinating.

Vaccination projects could also receive advice from experts, free loans of equipment such as traps, and free supplies of vaccines.