LONDON, England (Reuters) -- A British man was being treated for shock on Wednesday after he fell from a ladder while pruning trees, accidentally killing his wife with his chainsaw, police said.

The 56-year-old man, who has not been named, was cutting back tree branches at his home in southeast London on Monday when he tumbled backwards from the ladder.

The running chainsaw crashed down onto the neck of his wife, who was working in the garden below him.

"The woman was killed instantly, although she was not decapitated," police said in a statement. "Her husband was taken to hospital. He is still being treated for shock."

A police spokesman said the incident was being treated as a "tragic accident."