Queen Elizabeth terrified passengers with her high-speed driving

Samantha Cohen, 56, who became one of the Queen's most loyal and senior staff members after 18 years by her side, told the Sunday Times: "(The Queen would) drive her cars fast around Balmoral... (leaving passengers) white-knuckled."

The ex-aide added she was amazed Elizabeth had "no ego", and that despite being one of the world's most famous people, was the "antithesis of celebrity".

She said rather than being a show off who was intoxicated by her power, the Queen "took (her role in society) very seriously and performed it to perfection".

She added the late monarch was at her happiest when she was off-duty.

And she said she loved royal tours in Australia as she found them more relaxing as "there was less protocol" than in other countries including Britain.

Samantha got close to the Queen after joining the royal family press office around 25 years ago.

She was then promoted to the Queen's communications secretary, and her assistant private secretary.

Samantha first saw the woman who would become her future boss during the head of state's visit to Australia in 1977 during her Silver Jubilee year.

She was a schoolgirl in Brisbane at the time, and said she was "beyond excited" to see the then-Queen in the flesh.

During her role as a senior aide, Samantha saw Elizabeth nearly every day and accompanied on her official trips to Australia in 2002, 2006 and 2011.