In his maiden speech to Parliament in July 1987, Livingstone used parliamentary privilege to raise a number of allegations made by Fred Holroyd, a former Special Intelligence Service operative in Northern Ireland. Despite the convention of maiden speeches being non-controversial, Livingstone alleged that Holroyd had been mistreated when he tried to expose MI5 collusion with Ulster loyalist paramilitaries in the 1970s. Thatcher denounced his claims as "utterly contemptible". In September 1987 Livingstone was elected to Labour's National Executive Committee (NEC), although he was voted off in October 1989, to be replaced by John Prescott. As Kinnock tried to pull Labour to the centre, Livingstone worked to strengthen its socialist elements. He refused to pay the controversial poll tax until it was revoked, and was one of the 55 Labour MPs to oppose British involvement in the Gulf War in January 1991. Conversely, he supported NATO intervention in the Balkans, and the bombing of Serbia.