Anatoly Chubais, a key figure behind Russia’s post-Soviet economic transformation, had a largely ceremonial role as Vladimir Putin’s climate adviser when he left Moscow in March in a silent protest against the war in Ukraine. However, he has not spoken out against the president or the invasion. A family friend of Mr Tsoubais said on Sunday that the 67-year-old veteran reformer had been taken to intensive care at a European clinic and had been diagnosed with a rare neurological disorder. Ksenia Sobchak reported a message from Mr Chubais saying his condition was “moderate, stable” and that he suffers from Guillain-Barre syndrome, a rare disorder in which the body’s immune system attacks the nerves. His wife, Avdotya Smirnova, said Chubais was taken to hospital last week when he suddenly felt ill and lost feeling in his limbs. The room where the former Kremlin spokesman was staying has been inspected by officials wearing hazmat suits, according to Ms. Sobchak. Asked about Putin’s former adviser, Kremlin spokesman Dmitry Peskov said he was unaware of his condition and offered his best wishes. “This is certainly sad news. We wish him a speedy recovery,” he told Russian news agencies on Monday. Mr Chubais’ whereabouts are unknown, but Italian media have reported that since leaving Russia the former deputy prime minister has been spending time at his properties in Tuscany and Sardinia. La Repubblica newspaper reported that he was on holiday in Sardinia when he suddenly fell ill and was taken to a hospital on the island. Mr Chubais was one of the most powerful figures under President Boris Yeltsin in the 1990s, but lost influence when Vladimir Putin came to power. With few exceptions, President Putin’s disastrous war in Ukraine has not produced a wave of high-profile defections, and Mr. Chubais himself, who once championed liberal economic reforms in Russia, has remained silent. A flurry of suspected poisonings of Kremlin critics, including opposition leader Alexei Navalny, has reportedly made Kremlin officials wary of resigning or taking steps that could be seen by President Putin as betrayal. To many Russian opposition figures, Mr. Chubais’ illness looks like revenge on the Kremlin. “One thing we can be sure of: when Chubais felt that he had lost sensation in his limbs, he did not doubt for a second that he had been poisoned since he knows who Mr. Putin is, how he now sees him (Mr. Putin) and what does he do to people like him,” Leonid Volkov, an ally of jailed opposition politician Alexei Navalny, said on Sunday. The exiled activist said he did not regret Mr Chubais once confronting Navalny in a televised debate, as the former Kremlin adviser did not speak out against the war.