(BBC News) UK intelligence agents have been moved because Russia and China have access to classified information which reveals how they operate, a senior government source has told the BBC.
According to the Sunday Times, Moscow and Beijing have deciphered documents stolen by whistleblower Edward Snowden.
The government source told the BBC the countries "have information" that led to agents being moved but added there was "no evidence" any had been harmed.
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Mr Snowden leaked data two years ago.