Ewan McGregor had only been asleep for a few hours when the sirens started wailing.

It was 4.30 in the morning and this was the warning of an imminent mortar attack. The instructions were for everyone to throw themselves to the floor and pull on their armour-plated jackets and helmets.

It sounds like a scene out of a film, but this was for real. And, even though it turned out to be a false alarm, for Ewan it was a stark awakening to the dangers that face our brave troops every day in Iraq.

The Hollywood star had arrived at the British base at Basra just hours earlier - on a very special mission to honour a courageous young woman with a Pride of Britain award.

Despite the obvious risks, he was so impressed by the remarkable bravery of Britain's only female bomb disposal specialist in Iraq that he wanted to present the award to her himself.

It will be shown on the Mirror's Pride of Britain Awards on Wednesday on ITV1 at 9pm.

At the age of 32, Staff Sgt Michelle Cunningham was nominated by the Army for "displaying complete disregard for her personal safety" by singlehandedly extinguishing a fire at an explosives factory, in Middle Wallop, Hampshire, last year.

A man had already been killed and firefighters had decided it was too dangerous to go inside the blazing building.

But, even though she knew she could have been blown up at any minute, she entered carrying two fire extinguishers, went to the heart of the fire, got it under control and made safe hundreds of explosives.

An incredible act of courage. But for Michelle, and her unit, it was just another day at work, where danger is ever-present, facing threats of explosions, booby-trapped bombs, small arms fire and rocket attacks.

Ewan, 36, said: "I'm just so amazed by Michelle and her unit's courage. She's fantastic. I would never have the guts to do what she does. Most people, and I'm one of them, would run a million miles from a bomb but Michelle walks towards them and makes them safe. Amazing.

"When I was told about her, and was asked to come and present the award to her in Iraq, I said Yes because I really wanted to meet her and show my support.

"It's important that we should pay tribute to Michelle and people like her, who are prepared to put their lives in danger like this for others." Ewan got his first real sense of the risks that Michelle and all troops serving in Iraq face even before he arrived in the country.

After taking a military VC10 jet with troops from RAF Brize Norton in Oxfordshire to Qatar, the group transferred to a Hercules transporter for the two-hour night flight to Basra airbase.

As the plane entered Iraqi airspace, everyone aboard, seated shoulder to shoulder, was ordered to put on armour-plated flak jackets and helmets. Then they were plunged into darkness for what is termed a "corkscrew" landing - designed to counter the ever-present threat of being shot down by a missile.

Ewan's visit was a welcome morale boost for the 5,500 British servicemen and women at the base.

One airman, who took his photo on his mobile, joked to Ewan, who starred as Obi-Wan Kenobi in Star Wars: "May the forces be with you!"

Ewan met members of various regiments, who gave him an idea of the wide range of dangerous combat operations they undertake.

In the dog pound, he was attacked by an Alsatian trained to chase terrorists (fortunately, they gave him a protective sleeve to wear first!). He also rode on a Warrior armoured personnel carrier, saw its firepower, opened a new medical unit and flew in a Lynx helicopter.

Greeting him, General Graham Binns, commander of British forces in Iraq, said: "It's been a great morale boost that you've taken the trouble, not without personal risk, to come and show your support."

Ewan, whose brother Colin served until last year in the RAF as a Tornado pilot, said: "I've been so touched and in awe of the people I've met."

Perhaps no more so than the Pride of Britain winner Michelle and her colleagues in the Explosive Ordnance Disposal Regiment. After giving him a demonstration of the equipment they use to defuse bombs and carrying out a controlled explosion on a car, they invited him to wear a protective anti-blast suit, used when approaching explosives.

He said: "I can't imagine what it must be like to don that suit and walk out there in this heat with an explosive device to try and defuse."

As he presented Michelle, from Tewkesbury, Gloucestershire, with her Pride of Britain award, Ewan asked why she chose such a dangerous career.

Laughing, she said: "I didn't really. I used to work in Stores, ordering vehicle parts, and was sent on the wrong training course. I kept wondering why they were telling me how to defuse bombs, but I thought it was a cool job."

But, with surprising modesty, she added: "I'm no hero. I'm just doing a job. I love it. There aren't many jobs where you feel you can make a difference and people thank you."

Summing up his visit on British Forces radio, broadcast around the base, Ewan said: "We're all thinking about you back in Britain and we're all really proud about what you're doing here. We hope to see you back at home soon."