Milligan was Parliamentary Private Secretary to Jonathan Aitken, Minister of State for Defence, and was regarded as a "rising star" of the Conservative Party.

[2] Sunday Times editor Andrew Neil described Milligan: "He possessed an enquiring, original intelligence, a wide knowledge of foreign and domestic affairs and he was great fun to work with, his infectious laugh filling our editorial meetings, where he played a major role in defining the paper's policy positions".

Seen as a 'rising star' in the party and noted for his Commons interventions on foreign policy, he was appointed Parliamentary Private Secretary to Jonathan Aitken, Minister of State for Defence.

Milligan was found dead in his house at 64 Black Lion Lane, Hammersmith, London, by his secretary Vera Taggart on 7 February 1994.

[4] Milligan's corpse was found naked except for a pair of stockings and suspenders, with an electrical flex tied around his neck, his head covered and an orange in his mouth.

[4] Milligan's death was one of the scandals which contributed to the collapse of John Major's "Back to Basics" policy initiative, which was seen as emphasising socially conservative values.

The by-election was won by the Liberal Democrat candidate David Chidgey, who would hold the seat until the 2005 general election.