Police across the globe have successfully infiltrated leading dark web criminal markets. The result is that the trade in illegal drugs, stolen credit cards and indecent images of children is shifting to encrypted mobile phone apps. The crooks believe their business is protected by 'uncrackable' technology. So what should Government and the telecoms companies do to ensure criminals do not exploit secure encryption? Reporter: Geoff White Producer: David Lewis Editor: Gail Champion (Photo credit: NurPhoto\Getty Images)