"I'm just sick of it. So I've handed in my resignation."
She refused to take part in a Downing Street photo opportunity last July, saying: "Lots of nurses felt that the government hadn't led very effectively – the indecisiveness, so many mixed messages."
"It was just very upsetting."
Sir Keir Starmer, leader of the main opposition Labour party, said Ms McGee's resignation was a "devastating indictment of Boris Johnson's approach to the people who put their lives on the line for him and our whole country".
But Downing Street said: "This government will do everything in our power to support" staff of the National Health Service, stressing they had been excluded from a pay freeze affecting other public-sector workers.