Mr Berkshire is liaising with the Department for Environment and Rural Affairs (Defra) over the logistics of tackling farms' overcrowding concerns as adult pigs are not being slaughtered fast enough.

PPL Therapeutics (Edinburgh, UK), the company that, along with the Roslin Institute, cloned Dolly the sheep, announced on March 14 that it had created the first pigs cloned from adult cells.

A Yorkshire farmer has killed hundreds of piglets because labour shortages in local abattoirs mean adult pigs are not being killed fast enough. The resulting backlog means there is less space left ...