This plot to kill Lenin is depicted in the series Reilly, Ace of Spies, as Sidney Reilly (one of his many names) of British Intelligence was providing assistance. Reilly disappeared in Russia in 1925, probably killed by the OGPU, though there are rumors he was a Soviet double agent.
According to the series, Reilly wanted to grab power from Lenin. Howevever, can you imagine Russia being ruled by a guy named Sidney Reilly?
Hallelujah! Reilly is on DVD:
http://www.amazon.com/gp/product/B000742FZW/qid=1150832704/sr=8-1/ref=pd_bbs_1/104-0568209-0751915?n=507846&s=dvd&v=glance