Mrs Bush was also the mother of Jeb Bush, who served as governor of Florida from 1999 to 2007 and unsuccessfully ran for the White House in 2016.

As first lady, Mrs Bush went beyond the traditional role of a political spouse, founding the Barbara Bush Foundation for Family Literacy to help parents and children from disadvantaged communities to read and write.

'Family rock'

She was a fierce advocate of civil rights and went against many of her husband's Republican party supporters with her more liberal view on abortion rights.

In a statement from the White House, President Donald Trump said Mrs Bush would be long remembered for her devotion to country and family, "both of which she served unfailingly well".

Barack and Michelle Obama described her as "the rock of a family dedicated to public service" and as "an example of the humility and decency that reflects the very best of the American spirit".

Another former US president, Bill Clinton, said Mrs Bush was "feisty in support of her family and friends, her country and her causes".