The UK wants to know why three Russian submarines have apparently been examining the country's vital underwater cables and pipelines. 

British Defence Secretary John Healey says the subs were tracked over several weeks operating in the north Atlantic. 

Russia denies the claims. 

More than 90% of the UK's day-to-day internet traffic travels via undersea cables. 

Europe Correspondent Vincent McAviney told Ryan Bridge there's been no apparent damage; rather, the British Government is putting Russia on notice. 

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