The return to civvy street will be no holiday for soldiers haunted by the horrors of Iraq

Lt John McKeirnan knows what it means to be in the line of fire, to experience the confusion and terror of battle, and to confront the difficulties of coming home.

Lt John McKeirnan knows what it means to be in the line of fire, to experience the confusion and terror of battle, and to confront the difficulties of coming home.

He and the other soldiers from the 22nd (Cheshire) Regiment arrived back in Britain this week. Almost the first news they heard was that their regiment is to be merged into the 1st Battalion, The Mercian Regiment. They also have to adapt to life after the ambushes and mortar attacks of the supposedly "quiet" Basra area and have spoken candidly of their frightening experiences fighting Iraqi militants.

Lt McKeirnan said: "A mortar round goes through every nerve of your body. Indirect fire is so impersonal. You don't see your enemy. I can now understand the Second World War veterans - though ours was nothing compared - why they were shell-shocked, why some of them cracked up."

During their six-month "tour" of southern Iraq, the Cheshires and their 900-strong battle group of men and women were attacked 474 times, from mortars, rockets, roadside explosions, small arms and suicide bombers. Six soldiers died and more than six times as many were injured.

Lt McKeirnan recalled he was helping to escort water tankers through Basra when his company came under attack.

"A round hit the window - at first I thought it was a stone," he said. "My corporal said on the radio: 'We've got drama at the back.' I realised we were under fire and the two lads on top started opening up against the militia. For the first 10 seconds I panicked. The driver hit the gas because that is what we are trained to do. I had to say: 'Turn round and go back. We have five water tankers behind us and they can only go 30 miles an hour'."

For four miles they came under attack. One soldier was so terrified that someone had to hold his violently shaking legs.

In three weeks, 132 mortar shells landed on the soldiers' camp in the centre of Basra. Soldiers went to sleep wearing ear-protectors - or lay awake, waiting for the next strike.

A mortar shell landed just feet from Private Phil "Harry Potter" Beattie. "At one point I went to bits in August," he said. "I couldn't cope, couldn't sleep because of the constant mortaring, thinking where is the next one going to land, am I going to survive the next one?"

Lt Chris Somers, 26, will never forget the night of 29 August when he and his men were brought in by river to land in the heartland of the rebel leader Muqtada Sadr. "The streets were deserted and there were fires. It was eerie, like Apocalypse Now. They attacked with RPGs [rocket-propelled grenades] and machine-guns. I could see the green tracers. It was the first time I had ever been in a major contact ... I was terrified."

The Cheshires returned to England just days before 5 November - Bonfire Night. The explosions and the red of the fireworks were reminiscent of the RPGs, the green of machine-gun tracers. One soldier narrowly avoided crashing his car, another - 19-year-old Private Dave Greenaway - said: "I saw a red dot, like an RPG and dived over a fence into a bush in front of my mate."

Lt McKeirnan, who was reunited with his wife Jo, said: "After the euphoria of coming home, I started to get a bit tetchy and a bit nervy. I started going in on myself and being a bit withdrawn. I have no regrets but I will never again watch the telly and see other regiments going off to some shit-hole and wish it was me."

Many of his fellow soldiers admit arguing with their wives, being unable to talk to civilian friends, of finding it difficult to replace the daily adrenaline rush, and the "irrelevant" petty problems of life back home.

"A neighbour asked: 'Have you shot somebody?' I said I had and he would not speak to me for a week because he thought I was a mass murderer," explained 24-year-old L/Cpl Neil Buckley.

Captain Mark Ellwood, 30, said: "There is always the throwaway line: 'Wasn't it all a bit pointless?' That has started to get tiresome."

A few of the regiment have sought psychiatric help; one is currently in hospital.

Lt-Col John Donnelly, the commanding officer, believes that four weeks of sport and a "riotous show" by the comedian Jim Davidson have provided an opportunity for troops to let off steam. "Hopefully when I turn them loose on Cheshire for four weeks they will have told all their war stories and be ready for some fun. Everything a soldier has achieved means nothing if he gets himself into trouble or wraps himself round a lamp post," he said.