PurposeThe recent failures and insolvencies of organisations related to the modern methods of construction (MMC) have gained increased attention and controversy across the UK construction sector. Such failures are linked to their inability to achieve an economy of scale and drive key clients to accept the MMC as an alternative to traditional methods. This paper aims to unravel whether a phenomenon of “innovation negativism” has manifested and is contributing to public clients' indecision towards broader MMC, whether this is only linked to past negative experiences formed after the Second World War or whether additional contributing reasons exist to influence adoption.Design/methodology/approachThis study focusses on exploring the decision-making of the UK public construction sector; therefore, this paper adopts a qualitative approach, utilising interviews with 14 carefully selected MMC experts, government advisors and public clients. The phenomenological stance adopted herewith enables the authors to make better sense of the perceptions of the interviewees, leading to the conceptualisation of the innovation negativism phenomenon.FindingsThe paper identifies nine themes that may be argued to promote a profound understanding of the MMC negativism influencing public clients' decision-making. The study has found that more than just the previous negative perceptions formulated post Second World War are driving innovation negativism in the UK public sector. Notably, the emerging themes are incomprehension, lacking evidence, communication, relationship history, bad experiences, uncertainty, inadequate experimentation, the business case and localism.Originality/valueThis study is the first construction management research that acts as a fair departure point to conceptualise the reasoning behind innovation negativism in the construction setting. Through mirroring demand's unipolarity for traditional methods, policy and decision-makers can now rely on the conceptualised reasoning to determine practical solutions to overcome clients' indecisions towards MMC.