The percentage of dwellings using Modern Methods of Construction (MMC), including full-blown factory-made volumetric units, prefabricated components or panellised systems, has not grown significantly in the UK for a generation. Given its manifest advantages in speed, efficiency, build quality and energy performance, why is MMC not gaining ground in response to the acute housing shortage? Shortages of accurate and easily accessible data, a high overhead barrier for manufacturers and ingrained social attitudes that hark back to the prefabs of the 1950s all play their part. The expert panel proposes a way forward.