SIR Patrick Vallance, who played a crucial government role during the coronavirus pandemic, is to stand down as the UK's chief scientific adviser.

Prime Minister Boris Johnson said it was “impossible to fully convey” the scientist’s impact as it was announced he will leave the role at the end of his five-year term next April.

Vallance acknowledged his tenure was both “challenging and immensely rewarding” as a search for his successor was about to begin.

The 62-year-old, originally from Essex, was an academic and a consultant physician before joining GlaxoSmithKline, where he became president of research and development.

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He replaced Sir Chris Whitty as chief scientific adviser in 2018, and two years later they both became household names as leading experts and communicators in the fight against Covid-19.

Johnson said: “Sir Patrick may not have bargained for becoming a household name when he signed up for the job, but I am immensely grateful for his advice and expertise throughout the pandemic and beyond.

“He will be missed by all when he leaves next year, and I wish him the very best in all future endeavours.”

Vallance is expected to feature prominently during the official inquiry into the response to coronavirus.

The expert said he remains “fully committed” to the role, which also entails advising ministers on science and technology policy, until his replacement takes over.