A British farmer has been forced to put down most of his herd of so-called "Nazi cows" because they proved to be too aggressive and he feared they would kill someone.

The Heck cattle were originally bred in pre-war Germany as part of a Nazi plan to replicate the aurochs, an extinct species of giant cow that once roamed the forests of northern Europe.

But the beasts, bred for their long horns, shaggy coat and muscular appearance, turned on their keepers on Derek Gow's quiet Devon farm.

Mr Gow has worked with many different breeds, but none as nasty as this.

"If I was standing here and some of the aggressive ones were in this field and they could see me, then they would come right across now and try and kill me," he said.

"That's how aggressive they were."

At first Mr Gow tried to find new owners for his hoofed horrors, but perhaps not surprisingly, no-one offered to take them.

So after taking a personality test, the tamer cows were allowed to see another day, while the rest were slaughtered to be turned into sausages and burgers.

The animals were originally bred by German brothers Heinz and Lutz Heck in the 1930s, in a project backed by senior Nazis like Hermann Goering, who dreamed of releasing them into the wild for hunting.

The original aurochs, which was similar in size to a bison, is believed to have been extinct since the 17th century.