LONDON, June 23 (Xinhua) -- A grandmother aged 81 has become the oldest person to cycle the entire length of Britain in what is one of the toughest endurance tests in the country.

Mavis Paterson, who lives in Scotland, has earned herself a place in the record books after finishing the 1,545 kilometer journey from Land's End in Cornwall to John O'Groats in the far north of Scotland.

It took the grandmother 23 days to complete the gruelling ride, reaching John O'Groats on Saturday.

Guinness World Records confirmed in advance that Paterson would become the oldest woman to cycle the length of Britain if she successfully completed the distance.

Paterson decided to embark on the challenge in memory of her three children, who all died in the 40s within four years of one another. Her marathon has raised nearly 64,000 U.S. dollars for the charity Macmillan Cancer Support.

The grandmother was joined on the challenge by cycling companion Heather Curley.

She marked the completion of her journey by posting on her social media site: "It's hard to find the words now. After three weeks of an utterly unforgettable journey. We did it.

"So very, very grateful for all the support, the fun, friendships, cyclists who joined for a few miles."

Paterson said in a media interview: "I always set myself a goal and a challenge and it takes my mind off the grief that I suffer with losing my children."