The conservation watchdog has said the birds of prey were being targeted at their communal winter roosts and that over a year-long period it discovered six birds fitted with satellite transmitters had disappeared from the north Pennines.

The six missing birds vanished from parts of the north Pennines used for shooting – areas managed as grouse moors.

Natural England is claiming that hen harriers are particularly at risk from systematic persecution and disruption in these areas managed for rearing red grouse or game-birds.

A spokesman for the British Association for Shooting and Conservation (BASC) said it condemned any illegal killing of protected species.

Natural England chairman, Sir Martin Doughty, commented: “The hen harrier has unfortunately become the emblem of man’s callous disregard for the spectacular and majestic wildlife that we have in England.

“Following seven years of intensive monitoring and detailed research, the picture is unequivocal – hen harriers are being persecuted while they attempt to nest and birds are simply not returning to their breeding areas the following spring.”

BASC spokesman, Dave Harper, publicly commented on the claims: “Anyone within the shooting community who persecutes hen harriers is damaging shooting sports. Members of BASC who break the law and bring the sport of shooting into disrepute are disciplined and may be expelled, with the loss of shooting insurance and potential loss of shooting opportunity.”