Martin Alexander Baillie Reynolds CB CMG is a British civil servant who served as Principal Private Secretary to Prime Minister Boris Johnson from 2019 to 2022.

[3] On 10 January 2022, an image leaked to ITV News purported to show an email sent by Reynolds on 20 May 2020 inviting those at 10 Downing Street to "make the most of the lovely weather and have some socially distanced drinks" in the garden.

[12] On 3 February 2022 he resigned as Principal Private Secretary to the Prime Minister,[13] but was expected to remain in place until a successor had been found.

[15] In May 2022, following the release of the investigation final report by Sue Gray, it was revealed that Reynolds had boasted he had "got away with" rule-breaking at a "bring-your-own-booze" party in May 2020.

[19] He was additionally appointed a Companion of the Order of the Bath (CB) in the 2022 Prime Minister's Resignation Honours.