The Government has been accused at the Court of Appeal of acting unlawfully by allowing the latest badger culls to go ahead without an independent expert panel (IEP) to monitor whether the animals are being killed in a humane way.

The Badger Trust is asking three appeal judges to rule there was a "legitimate expectation" that an IEP would be put in place.

The challenge arises from a decision to sanction a second year of "controlled shooting" of free-roaming badgers in Gloucestershire and Somerset as part of efforts to tackle tuberculosis in cattle.

The Government says the disease led to the slaughter of more than 26,000 cattle in England last year and multimillion-pound losses.

Culling is under way and today's case is expected to provide legal guidance for future culls.

The Department for Environment, Food and Rural Affairs (Defra) is using the two pilot schemes in the West Country to test whether the shooting method can be rolled out to other parts of England.

Opponents say culling is inhumane and ineffective and alternatives such as vaccination should be pursued. Defra says this year's programme will be independently audited.

Last year, the first year of the four-year pilot programme, an IEP reported that controlled shooting could not deliver the level of culling needed to bring about a reduction in bovine TB and was not humane.

Defra decided to continue the programme this year without an IEP in place.

Environment Secretary Elizabeth Truss is being accused of breaching a substantive legitimate expectation that an IEP would monitor the entire pilot cull.

Mr Justice Kenneth Parker recently ruled at London's High Court that there were "no plausible grounds" to support the claim.

Today the Badger Trust asked Lord Justice Davis, sitting with Lord Justice Christopher Clarke and Lord Justice Bean, to rule that the single judge went wrong in law and a legitimate expectation had been made out.

David Wolfe QC, appearing for the trust, agreed with Lord Justice Davis when he said: "The law is not in dispute. The question is how it is to be applied in the circumstances of this case."

Mr Wolfe said the Protection of Badgers Act 1992 made the killing of badgers a criminal offence. The case was about the specific circumstances in which the Government could allow environmental conservation body Natural England to issue licences for the animals to be culled without committing a criminal offence.

The trust says there can be no proper independent assessment of the safety, effectiveness and humaneness of the culling operation without an IEP.

Professor Tim Coulson, a member of the 2013 IEP, said the panel's report clearly showed the rationale for ensuring independent monitoring continued.

He said: "If this scientific advice is ignored then the data collected during the 2014 culls will be insufficiently reliable for assessment of humaneness and effectiveness.

"This means that farmers, veterinarians and scientists intimately involved in controlling bovine TB will be denied the information necessary to allow them to assess whether the IEP's recommended changes to the culling process have corrected the failings identified by the pilot culls."

The Government and farmers insist that culling is necessary to tackle TB in livestock.

A Defra spokesman said: "It would not be appropriate to comment on ongoing legal proceedings. However, we have always been clear that the independent expert panel's role was to oversee the six-week pilots in the first year of the culls.

"We have acted on their recommendations to improve effectiveness and humaneness and this year's programme will be independently audited.

"Overseas experience shows a comprehensive strategy is the way to make England disease free. This includes cattle movement controls and vaccinating healthy badgers, which could play an important role in preventing the spread of bovine TB to new areas of the country. A responsible and effective approach must also include culling in areas where the disease is rife."

At the end of a one-day hearing, Lord Justice Davis reserved judgment and said the court would give its decision as soon as possible.