Lenin's return to Russia with help of the German High Command to end the war on the Eastern front to allow Germany to concentrate on defeating the Western allies:
"On 9 April 1917, Vladimir I. Lenin returns to Russia from Switzerland with 30 other revolutionaries. The trip by train has logistical and financial support from Germany. Germany’s leaders hope that, with Lenin’s support, revolutionary events in Russia will be spurred on, and a Russian military defeat can be expedited.
These expectations are not disappointed. A few months later the „October Revolution“ begins in Russia. The country, shaken by civil war, is forced to take up peace negotiations with Berlin, and in March of 1918 the Treaty of Brest-Litovsk is concluded."
http://www.bwbs.de/bwbs_biografie/Le...ssia_B694.html
As always, good planning by the Germans but the execution fails.
This event has changed world history.
A dead Lenin would have been to the interest of Britain, yes.