COUPLE’S ILLNESS RAISES FEAR OF NEW RUSSIAN ATTACK.

• Four months after a quiet corner of England was plunged into a Cold Warstyle saga of spies, chemical weapons and international tensions, residents are wondering whether it is happening all over again.

Counterterrorism detectives and local police are investigating after a couple in their 40s fell critically ill from exposure to an unknown substance a few kilometres from where a former Russian spy and his daughter were poisoned with a nerve agent in March.

Scientists were working to identify the substance amid speculation the victims could have been sickened by residue from the poison that nearly killed Sergei and Yulia Skripal.

Wiltshire police declared the case a “major incident” Wednesday, four days after the man and woman were found collapsed at a residential building in Amesbury, 13 kilometres from Salisbury, where the Skripals were poisoned.

Residents felt a grim sense of deja vu.

“With the Russian attack happening not long ago, we just assumed the worst,” said student Chloe Edwards, who said police and fire engines descended on a quiet street of newly built homes in Amesbury on Saturday evening.

Police said officers were initially called Saturday morning about a collapsed woman, then were summoned back in the evening after a man fell ill at the same property. Police at first thought the couple, identified by friends as Dawn Sturgess, 44, and Charlie Rowley, 45, had taken a contaminated batch of heroin or crack.

“However, further testing is now ongoing to establish the substance which led to these patients becoming ill,” said Deputy Chief Const. Paul Mills.

British media reported that samples of the mystery substance had been sent to the Porton Down defence research laboratory for testing.

Prime Minister Theresa May’s office said she was being kept updated on the case, “which understandably is being treated with the utmost seriousness.”

The emergency services’ response echoes that in the case of Sergei Skripal, 67. The former Russian intelligence officer was convicted of spying for Britain before coming to the U.K. as part of a 2010 prisoner swap.

He had been living in Salisbury, a cathedral city 145 kilometres southwest of London, when he was struck down along with his 33-year-old daughter Yulia.

The Skripals’ illness initially baffled doctors after they were found unconscious on a park bench in Salisbury. Scientists concluded they had been poisoned with Novichok, a type of nerve agent developed by the Soviet Union during the Cold War.