Badger culling may have a far greater impact on reducing bovine tuberculosis in cattle than was previously thought, a study has revealed.

A group of researchers from the Imperial College London and the Institute of Zoology has continued to monitor the culling areas of the Krebs badger culling trial and has found that TB cases in cattle continued to decline after the trial ended.

In the first year after the trial a decline of 48% in herd breakdowns was recorded, while breakdowns fell by another 60% the following year.

Both figures are far higher than the average 23% seen for the first four years of the trial.

The research also shed new light on so-called perturbation – the effect seen when the upheaval of culling causes previously distinct badger groups to break up and spread the disease into areas neighbouring the trial zone.

Perturbation was a major reason why DEFRA secretary Hilary Benn said no to a badger cull, but the report said that the impact of perturbation declined over time.

“Beneficial effects inside culling areas increased in magnitude and detrimental effects were no longer observed on neighbouring lands,” the report stated. The report findings prompted National Beef Association acting chairman Bill Harper to challenge the DEFRA secretary to honour a pledge made when he announced the no-cull decision in the summer.

“Mr Benn said he would take account of any new evidence. Well this is it.

“This work shows that the disease can be tackled,” said Mr Harper. “There will be no cost to the government. We will bear the cost,” he insisted.

Mr Harper also questioned why the research had not been presented to the Independent Scientific Group on TB.

“This is the most important piece of research that we have seen for two years and yet it has not been brought to the attention of the group.

“I cannot believe that no one knew about it. Someone must have seen it. It was published in the spring. Where has it been?”

The leader of the research, Helen Jenkins of the Institute of Zoology, was also unable to explain the lack of publicity the report had received.

But she urged caution on the findings and said the report’s conclusions should be seen in the wider context of the trial.