LONDON, Nov 13 (Reuters) - Britain said the bosses of

social media companies and online marketplaces could be

personally fined if they fail to tackle the sale and promotion

of dangerous and illegal knives on their platforms, under

proposals published on Wednesday.

Interior minister Yvette Cooper said an epidemic of knife

crime was devastating families and communities across the

country, and the government had set out a mission to halve it

over the next decade.

"That means tough new sanctions for technology executives

who fail to tackle illegal knife sales on their platforms, and a

comprehensive ban on ninja swords," she said in a statement on

Wednesday.