Franz Klintsevich, a retired colonel, was responding to comments from Defence Secretary Michael Fallon, who said "in the most extreme circumstances, we have made it very clear that you can't rule out the use of nuclear weapons as a first strike."
Mr Klintsevich said if Britain were to launch a preemptive strike, then "not having the biggest territory, it will literally be erased from the face of the earth."
Sir Michael's comments came in response to Labour divisions over retaining the Trident deterrent, with Labour leader Jeremy Corbyn suggesting renewal might not be in the party's election manifesto — only to be corrected later by party colleagues.
Speaking to BBC Radio Four's Today Programme, Sir Michael said Labour had left voters "completely unsure as to what would actually happen to our nuclear deterrent."
He said Prime Minster Theresa May would be ready to use Trident as a "pre-emptive initial strike".
"In the most extreme circumstances, we have made it very clear that you can't rule out the use of nuclear weapons as a first strike," he said.
Asked in what circumstances, he replied: "They are better not specified or described, which would only give comfort to our enemies and make the deterrent less credible. The whole point about the deterrent is that you have got to leave uncertainty in the mind of anyone who might be thinking of using weapons against this country."
Comment: There is no doubt in Russian minds that if posturing little Britain were stupid enough to attack Russia, it would be their last act.
Mr Klintsevich, who is deputy chairman of the upper house of the Russian parliament's defence and security committee, called Sir Michael's comments "disgusting" and said it "deserves a tough response".
Comment: Absolutely. The British elite have a long history of disgusting words and deeds, most of which have never been condemned.
He added: "In the best case this statement should be taken as an element of psychological war — which looks particularly disgusting in such a context.
"Otherwise, it sounds really bad, because a reasonable question arises: Against whom is Great Britain going to preemptively use nuclear weapons?"
Comment: A reasonable question indeed. Perhaps Theresa May will elucidate the British public before the general election in June, so they might make a more informed choice as to whether or not they want her and her Tory party zombies to rule over them.
If Britain intended to use nuclear weapons against a non-nuclear state, he added, "then probably English people desperately want to share the laurels of the USA who threw nuclear bombs at defenceless [Japanese cities] Hiroshima and Nagasaki [in 1945]."
"But those times have gone for good, as has the era of the greatness of the British Empire."
Comment: This is an absolutely appropriate and accurate response to the delusional, impetuous and arrogant bellicosity of the repugnant British Defence Sec. Michael Fallon. All right-thinking English people should be supporting the words of the Russian MP and lobbying their wanna-be dictator politicians to shut the hell up, before they get them all killed.