A British TV presenter has told of her relief that her two missing sons were rescued - after they ignored her warnings and hiked alone up a volcano.

Katherine Forster, a politics reporter on GB news, said brothers Matthew, 22, and Andrew, 18, used ‘scout training and knowledge from Bear Grylls videos' to help them survive by gathering rainwater and building a shelter on Mount Agung, in Bali, Indonesia.

The pair trekked up the active volcano on Tuesday night July 2 but became lost and their phones died. Worried friends lost contact with them and contacted Katherine on Thursday morning - by which time her sons had been missing for 30 hours.

Local rescue teams launched a mass search with officials fearing the lads would be unable to survive on the treacherous route without a guide.

They were finally found at around 6 pm local on July 4 - more than 40 hours after they set off.

Relieve Katherine said the boys had boarded a plane to return home - but not before ‘strong words' were exchanged about their decision to try and tackle the mountain alone without friends or a local expert hiking guide.

She said: ‘On Friday morning I should have been outside No 10 reporting. More importantly, my two eldest sons should have arrived home after a nine-week adventure across Southeast Asia. But they didn't.

‘They weren't on the flight. They'd hiked up 3000 metre high volcano Mt Agung starting 2.30 am Wed (8.30 pm Tues night BST) to see the sunrise. Their phones died near top. I didn't know. By the time a friend of theirs contacted me early Thursday morning, they'd not been heard from in 30 hrs.

‘Luckily they'd been in touch with friends going up. And a Swedish friend, Sarah, who they'd met in Vietnam had reported them missing to the British Embassy on Wednesday night.

Thursday was the worst day of my life. But friends dropped work & came round. Made phone calls. Our tech-savvy young friends & friends of friends spread the boys' pictures and last known location across social media. The Foreign Office were amazing. Local rescuers scoured the volcano.

‘Then suddenly it was the best day of my life. 40 hours after they'd set off, they were found. Weak but alive. The first rescuer to reach them said they thought they'd be dead. Three dozen search and rescue, police, fire saved their lives.'

Katherine thanked the local Karangasem Rescue team and the British Foreign Office as well as her son's friends who had helped to make appeals to find them

She added: ‘Rescuers saved them. But so did you. They are beyond lucky to live to tell the tale.'

Officials said they were told of the missing boys and were dispatched to the scene, where they found an abandoned rental motorcycle near a hiking trail rarely used.

They called the phone number on the bike and the rental shop confirmed it had been taken out by the two lads. The owner told officials they were 'excited' about going to the top of the volcano, which is the highest point in Bali.

Despite the thick fog and poor visibility hampering the search, rescuers found the Brits safe but exhausted at around 6 pm local time the next evening on July 4.

Head of Basarnas Bali I Nyoman Sidakarya said: 'From the information of the community and the team, there was a sound of someone screaming for help.

'At 18.15 WITA, the location was found, and the tourists were discovered in good health at an altitude of 1,700 metres above sea level.

'They are lucky to have survived. The conditions on the volcano are very dangerous.'

Coordinator of the Basarnas Karangasem Search and Rescue Post I Gusti Ngurah Eka Wiadnyana added: 'When we found them, both were in a limp state due to exhaustion. However, both of them could still go their own way down the mountain.'

The hikers said they became lost during the descent because they did not memorise the path back to their motorcycle.

They were given first aid and were taken to the Bebandem Police Station for questioning.

Mount Agung is an active volcano and the highest point on Bali at an elevation of 9,944ft (3,031 meters).

The Balinese Buddhist Hindus considered the mountain to be sacred and traditionally believed it to be the 'Navel of the World'. Many temples are built on the slopes of the mountain including the mother temple of Besakih.