The Guardian has appointed Katharine Viner as its new editor, the first woman to hold the post in the paper's almost 200-year history.

Viner, who is currently deputy editor and the editor-in-chief of its American operation, takes over from Alan Rusbridger, who is to stand down this summer after 20 years at the helm.

Viner will be just the 12th editor in the paper’s history.

Following the announcement, Viner said to The Guardian: “Being editor-in-chief of the Guardian and Observer is an enormous privilege and responsibility, leading a first class team of journalists revered around the world for outstanding reporting, independent thinking, incisive analysis and digital innovation.”

“Building on (Rusbridger’s) track record, I intend to lead a media organisation that is bold, challenging, open and engaging. It will be a home for the most ambitious journalism, ideas and events, setting the agenda and reaching out to readers all around the world.”

Rusbridger has tweeted his congratulations, as well as passing on some advice from editors who came before him.

Best advice on editing came from the 8th editor (AP Wadsworth):"There’s nothing in it; just don’t do anything bloody silly"

— alan rusbridger (@arusbridger) March 20, 2015