Two Britons who went to Syria to fight IS have told of their battles on the front line - and how they vowed to kill each other rather than get captured.

Jamie Read and James Hughes told how they dodged bullets during chaotic patrols with Kurdish forces after recording a "goodbye" video for their families in case they died.

They described spending hours lying in the "pitch black" in no-man's-land, in conditions they said were reminiscent of World War One.

On one occasion, it was so cold that a young Kurdish comrade collapsed with hypothermia - "body-popping" on the ground next to them.

In an exclusive Sky News interview after their return to the UK, the pair also revealed how panic alarms have been installed in their homes, amid fears they could be targets for IS supporters.

They strongly denied being mercenaries, telling how they had sold possessions to fund their flights and had returned to the UK to "mounting debts and bills".

They had not been paid "a penny" for their exploits, though they had been "treated like royalty" by some of the Kurdish troops, the men said.

The former soldiers gave a detailed account of their time in Iraq and Syria, explaining that they had travelled to fight IS militants because they had "zero tolerance for terrorism".

Describing what had prompted them to travel, Mr Read said that the beheading of British aid convoy volunteer Alan Henning had been the final straw.

"Alan Henning - aid worker, British - put him on his hands and knees and cut his head off, you know what I mean," Mr Read said.

"Can you really find justification in sitting back here and doing nothing?"

Mr Read, 24, and Mr Hughes, 26, revealed that organising the trip had been quite simple with a "phone call here or there" and some communication over Skype.

The screening process had amounted to checking their posts on Facebook and ensuring that social media friends were not IS supporters, Mr Read said.

The pair said that after arriving in Irbil, northern Iraq, they were transported via the Kurdish HQ to the front line in Syria.

During the journey the Britons said they had no idea whether they had landed in a trap.

"I'm not going to lie, this was one of the most frightening processes you can go through, you know, the paranoia - through the roof," Mr Read said.

"You get picked up by a guy who doesn't speak English, so straight away there's a language barrier.

"When we got to the safe house - it's sort of dodgy-looking, so you think 'I don't really like this'. At one point, you think 'is this the point I'm going to get handed over?'"

After getting a uniform and weapons, Mr Hughes said they eventually "rocked up" on the frontline to an old schoolhouse covered in mud.

They arrived to cheers from their Kurdish comrades, were plied with chai (tea) and cigarettes, and met with three other Westerners who had joined the fight.

During their three weeks on the front line, their duties included terrifying night patrols where it was the "blackest black... like being in a cave with no lights".

"You are left staring into the pitch black, hoping no-one sees you first," Mr Read said.

The Britons said they had hatched a plan to shoot each dead rather than being caught and paraded on television as hostages.

"We wouldn't get captured, bottom line, we couldn't get captured, we're not getting our heads paraded on YouTube, we made that vow before we went out.

"Everybody out there is carrying a round for themselves. Nobody wants to be captured by IS. Nobody wants to end up on YouTube getting their head cut off.

"So for us, as harsh as it sounds, it's probably the better way to go. It's the old saying 'you keep a round for each other'."

Describing their final day, Mr Read told how the pair had been out on patrol towards a nearby village where IS militants had been holed up.

"All of a sudden we just got opened up on. Quite a lot of small arms (...) quite a lot of AKs and they were quite close.

"There were rounds coming in and they were really close - they were pinging and they were bouncing, whizzing over your head - obviously it's a very distinctive noise.

"There was a lot of shouting, a lot of screaming, a lot of F-words being dropped."

The pair said that they were forced to flee through a village which was "littered with IEDs (improvised explosive devices)" before returning to base ahead.

"We eventually made it out but this was a real eye-opener - this is how these people were going to act - there's something more that needs to be done there."

They returned to Britain last week and were questioned by anti-terrorism officers for six hours at Heathrow before being released.

Asked whether they would return to Syria, Mr Read said: "I'd like to think we would have the opportunity to go back."

But he added: "I'm unsure on the political stance - I'm not sure whether our Government would appreciate us going back."

(Sky news)