The March 4 attack on Skripal and his daughter in the English city of Salisbury has triggered a wave of tit-for-tat expulsions of diplomats between the West and Russia and sent relations plunging to new post-Cold War lows.
"This could be in the interests of the British government which found itself in an uncomfortable situation having failed to fulfil promises to its electorate about the conditions for Brexit," Lavrov said at a press conference in Moscow, referring to Britain's planned departure from the European Union.
Lavrov also suggested that the poisoning of Sergei Skripal and his daughter "could also be in the interests of the British special forces who are known for their abilities to act with a licence to kill".
"There could be a whole number of reasons and none of them can be ruled out," Lavrov said.
Britain has said it was "highly likely" that Russia was responsible for the attack using a nerve agent developed in the USSR, a view backed up by its Western allies.
But Russia denies any involvement and has called for Britain to give it access to the nerve agent used.
"Britain, I think, will not manage to evade answering these questions. Because they are already only too obvious and it's only too obvious that our British colleagues have lost their sense of reality."
Lavrov complained that the British authorities have still not give consular access to "our citizens," and that the situation had not changed despite Yulia Skripal's improved condition.
He said he hoped Sergei Skripal would "also follow this example" and get better.
Lavrov also denied the attack was "sophisticated," saying that if it had been, the victims would have died immediately.
"If I understand correctly, sophisticated attacks usually lead to instant death," he said.