Owen Paterson, the Environment Secretary, will declare that the pilot badger cull has been a success, but admit that ministers have nearly halved targets for the number of animals to be killed.
Farmers were licensed to shoot a total of 4,940 badgers in west Somerset and west Gloucestershire in moves the Government argues are essential to curb the spread of bovine tuberculosis in cattle.
That figure is being reduced to 2,670 after the Department for Environment Food and Rural Affairs (Defra) slashed estimates of the number of badgers in the two areas targeted for a cull.
It believes the badger population could have slumped because of last year's harsh winter and a lack of food for the animals.
The programme has proved highly controversial with demonstrations by animal rights activists and warnings that it could prove counterproductive by dispersing infected animals across the country.
Mr Paterson will tell MPs today that ministers regard the Somerset cull, which has just ended, as a success with 850 badgers killed over 40 days. This is still short of a revised target for the county of 1,020.
The Environment Secretary will announce that the culling company is applying to Natural England, which is overseeing the programme, for a short extension of the cull in Somerset in an effort to enable it to hit its new target.
A Defra source said the Somerset cull was making “very good progress... but an extension could make more progress towards that target”.
The source said the pilot “appears to have been successful” with no concerns over the safety or humaneness of the programme.
“The chief vet has advised this outcome should deliver clear disease benefits as part of a four-year cull,” he added.
The target for the number of badgers to be shot in Gloucestershire, where the cull ends next week, is being cut from 2,860 to 1,650.
The source denied that the targets had been reduced to help portray the cull as a success. He said the original calculation of the badger population that the culling company was operating against was “almost certainly the right estimate” in 2012. He said: “As soon as we got new data we updated that.”
The source disclosed that 240 culled badgers had been examined to check whether they had been humanely killed, with concerns raised over the shooting of one animal.