Conservative MP Angela Richardson has resigned as a ministerial aide to Michael Gove over partygate.
She is the first MP to quit over the report published by Sue Gray on Monday, January 31.
Ms Richardson has served as the MP for Guildford since 2019.
She shared her "deep disappointment" over the handling of the Partygate affair and said only "full disclosure" would rebuild trust.
A statement said: "I would like to thank constituents for your patience in waiting for the publication of the Sue Gray report and the response from the Prime Minister today before I issued my statement.
"Sue Gray's report published today clearly states there were failings at Number Ten Downing Street that let us all down. The Prime Minister again apologised for those.
"I share the deep disappointment that it has taken so long to get to this stage when there could have been an early acknowledgment and apology.
NEW: Conservative MP Angela Richardson said she has resigned as a ministerial aide to Michael Gove as she shared her “deep disappointment” at the handling of the partygate affair pic.twitter.com/rcWMbnc9gc
— Darren McCaffrey (@darrenmccaffrey) January 31, 2022
"It also seems as though there are further questions to which we do not yet have the answer because of the Metropolitan Police investigation.
"I echo my colleagues who called on Number Ten, when appropriate, to release in full the details of events considered by Sue Gray but not currently included in her report.
"Only that way - with full disclosure - can the process of rebuilding trust begin.
"Last week, I stepped back from my governmental responsibilities to invest more of my time releasing the campaign that I am working on for the people of Guildford, Cranleigh and our villages.
"In doing so, I will have more freedom to fulfill my promise to you as I hold the government to account, as a critical firend, on the issues that matter most to the people of Guildford.
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