During the 1970s, Leadbeater became active in the New Zealand arm of the
Campaign for Nuclear Disarmament, which had been founded by her mother Elsie Locke. During the 1980s and 1990s, Leadbeater served as the media spokesperson for the Campaign for Nuclear Disarmament, which successfully campaigned for a
New Zealand nuclear-free zone and a ban on visits by nuclear-armed and nuclear-powered ships. She was also involved in various other human rights, peace, anti-
Apartheid and solidarity groups including the Auckland East Timor Independence Committee, the Philippines Solidarity Network of Aotearoa, the Indonesia Human Rights Committee and the Palestine Human Rights Committee. In 2001, she attended an
anti-globalisation conference in
Jakarta called the Asia Pacific People's Solidarity Conference, which had been organised by Indonesian non-governmental organisation INCREASE (the Indonesian Centre for Reform and Social Emancipation). The conference was disrupted by members of the fundamentalist
Ka'bah Party who were armed with machetes and knives. Indonesian police stood by and subsequently arrested the conference participants. Leadbeater was part of a group of 32 foreigners who were detained and threatened with deportation by Indonesian authorities. Leadbeater has written about New Zealand's role in facilitating the
Indonesian invasion of East Timor and the anti-nuclear movement in New Zealand during the 1980s. Leadbeter has criticised the NZSIS and
Government Communications Security Bureau for spying on New Zealanders and allegedly serving the interests of the
Five Eyes powers over New Zealand. Leadbeater has argued that the intelligence services' claim to combat "subversion and security threats" were a smokescreen for "targeting people and movements who disagree with the political status quo." ==Writings==