In the three years since the law on adult deceased organ donation consent in England changed to include an opt-out system, there has been no discernible change to donation rates. The lack of a positive impact on donation rates was predicted by many of those who took part in debates before and during the passage of the Bill through Parliament. This invites the question as to why England moved to an opt-out system for organ donation despite equivocal evidence of likely benefit and opposition from expert health professional organisations. To address this question qualitative analyses of Parliamentary debates on organ donation was undertaken. This revealed a shift from a dominant position, which gave primacy to the evidence of likely effects, towards a more normative position where a deemed consent option was viewed as the 'correct thing to do' and the limited and conflicting evidence viewed in a positive light. By 2017, following Wales's move to an opt-out system, together with continued lobbying for similar changes for England by professional and patient groups, alongside sustained public popularity for organ donation, the balance of opinion had shifted towards a system where deemed consent would become the default position for most English adults.