ITV News presenter Alastair Stewart has stepped down from his role following what ITN called “errors of judgement” in his use of social media.

ITN said he had breached editorial guidelines, but did not elaborate on the reasons for his departure.

The presenter said, in a statement: “It was a misjudgement which I regret.”

He added: “It’s been a privilege to bring the news to households throughout the UK for the past 40 years.”

Following the announcement, a tweet emerged in which the 67-year-old quoted Shakespeare at a black Twitter user, including the line, “his glassy essence – like an angry ape”

The newsreader’s Twitter account has now been deactivated.

Stewart began his career at Southern Television in 1976 before moving to ITN, where he spent three years at Channel 4 News before becoming a mainstay of ITV News.

He was awarded an OBE in 2006 for services to charity and broadcasting.

Former ITN colleague Julie Etchingham said via Twitter: “So sad to learn this – we have worked on many big stories together & Al is a trusted friend and guide to many of us.”

ITV News newsreader Mary Nightingale said in a tweet: “Very sad about the departure of Alastair Stewart. He was a good friend and mentor to me when I started at Carlton TV, and we worked together for more than 27 years. I will miss him.”

ITN’s chief executive Anna Mallett said: “We would like to recognise Alastair’s contribution as one of the UK’s foremost journalists and TV presenters and to thank him for his commitment to delivering high-quality broadcast news over many years.”