Now, the devoted grandmother, who has already raised more than £1,600, is taking on the gruelling 1,000 mile trek to say thank you.

She said: "I can't wait – this is by far the biggest challenge of my life and I'm just glad to be able to put something back.

"I did a 400km ride along the River Nile in the past but this is an even bigger challenge for me. It's very exciting."

Sandra's grandson Luke, who lives in Blackburn, had to undergo open heart surgery at Alder Hey Children's Hospital when he was just 14-months-old to correct a condition called coarctation of the aorta.

Now the youngster has started school but he could need more operations in future.

The 46-year-old midwife said: "Every year, thousands of people die prematurely from heart disease. It remains the UK's single biggest killer.

"The British Heart Foundation is the nation's heart charity and every day they save lives."

Sandra and pal Amanda Chinnery, from Blackburn, will be riding 80 miles a day during the gruelling challenge.

During the first week they are being supported by Sandra's 72-year-old parents Terry and Glenda West, from Chorley, who will cook all their meals and make sure their tents are properly assembled each night.

Husbands Geoff Woods and Gary Chinnery will be on hand to help during the second part of the challenge.

On Friday, August 1, big crowds are expected when the pair pass The Pines Hotel, in Preston Road, Clayton-le-Woods, at the half way point of their journey.

To pledge your support call 01772 457009 or visit www.bhf.org.uk.