AN intrepid father-of-two from is hoping to reach the summit of the world's highest mountain early next week.

Steve Graham, a Darlington self-employed heating engineer, is heading for the peak of Everest, where temperatures can drop as low as -60 degrees centigrade.

Steve, 45, made an emotional final telephone call from base camp to his wife Hollie on Thursday morning before setting off on the final climb to just over 29,000 feet. He hopes to reach the summit on either Monday or Tuesday.

Hollie said: "It was hard to say goodbye but I understand his passion and why he needs to do this."

The experienced mountaineer is raising money for St Teresa's Hospice and Prostate Cancer UK, and is carrying a flag bearing the logos of the charities as well as three Darlington primary schools that have supported him – Mowden, Abbey and Reid Street.

Steve, who lives in Mowden, has already conquered many of the world's highest mountains, including Aconcagua, Kilimanjaro, McKinley, Elbrus, Vinson, Carstensz Pyramid, and Mt Blanc in the Alps.

His ultimate aim is to climb the highest mountains on each of the seven continents and he has adopted the nick-name "Seven Summit Steve".

In his latest Instagram message, Steve says: "I just wanted to say a final thank you before setting off to each and everyone of you that has sent me messages of support along the way."

He adds: "Friends, family, friends of friends, people I have never met; I am truly humbled. I hope you have enjoyed the photos I have sent so far, hopefully the next one will be me on the summit. It has been an incredible journey, both physically and mentally challenging, with possibly the toughest part ahead."

Steve, who has two sons – Sam, 16, and Max, nine – set off for Everest on March 25 with an expedition team from the Jagged Globe organisation.

Hollie said: "It's obviously a nerve-wracking time for us all but we know he's got a lot of experience and he knows his limits. I've had plenty of wobbles along the way, worrying about him, but I just want him home safely."

Before he left, Hollie gave Steve a special amethyst stone that she's had from being a teenager as a good luck token. "I just wanted it to be with him for protection," she said.

Steve's progress can be followed on Instagram by searching for "7summitsteve". To make a donation to his charities, go to www.virginmoneygiving.com/7summitsteve