Sedley has provoked considerable debate about the role of government in collecting and keeping DNA samples. At present criminal suspects detained by the police in the UK are automatically given cheek swabs and their DNA kept, in perpetuity, by the government. This has created the situation where different races are differently represented in the United Kingdom National DNA Database. On the grounds that this situation is indefensible, Lord Justice Sedley discussed the case for a blanket DNA collection policy, including collecting samples from all visitors to the UK.
Ian McEwan said of
Ashes and Sparks: Essays on Law and Justice (Cambridge University Press, 2011) "you could have no interest in the law and read his book for pure intellectual delight, for the exquisite, finely balanced prose, the prickly humor, the knack of artful quotation and an astonishing historical grasp". In February 2012, the
London Review of Books published an essay by Sedley in which he criticised soon-to-be Supreme Court Justice
Jonathan Sumption's FA Mann lecture. In this lecture, Sumption had argued that the judiciary had overstepped the boundary between its legitimate judicial function and illegitimate political decision making in the context of the remedy of
judicial review. The critique centred on Sedley's conceptions of the precise interplay of the judicial, legislative, and executive branches, and made reference to the grey areas within which Parliament had not expressed any set opinion. ==Notable appointments and offices==