You're reading: Guardian: Former Russian spy critically ill in UK ‘after exposure to substance’

One of the two people critically ill in a Salisbury hospital after “suspected exposure to an unknown substance” is a Russian man who was exchanged in a high-profile “spy swap” in 2010, the Guardian understands.

Sergei Skripal, 66, was one of four Russians exchanged for 10 deep cover “sleeper” agents planted by Moscow in the US.

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