Don McCullin cuts a haunted figure when he talks about his career as one of the most celebrated living war photographers. It’s a mantle which he wears reluctantly today and one which weighs heavily on his shoulders. I know all this of course because over the past few months McCullin, now 75, has been all over the media promoting Shaped by War, his retrospective that is currently on show at the Imperial War Museum in Salford Quays. But hearing him speak in person yesterday reinforced the feeling that this is a man haunted by what he’s seen and what his photos – and all great photojournalism – have ultimately failed to do, despite all the hyperbole: ie jolt world leaders into forcing change.

The event itself was a disappointment if I’m honest. The venue was poor, the sound was terrible – seated two-thirds of the way back we didn’t actually hear the first four questions, and as staff scrambled to sort out the levels there were numerous loud feedback screeches.

McCullin was on form – albeit visibly weary of the whole publicity circus which has surrounded the exhibition (which is great, by the way). Having read his autobiography Unreasonbable Behaviour, and having attended his In England show at Bradford’s National Media Museum last year, I know what a toll his work took on his personal life. Still though, there’s something very sad about hearing such an incredible photographer and journalist saying that looking back, he didn’t think any of it was worthwhile.

“What purpose did any of it actually serve?” he asked early on. “People talk about the [Nick Ut] photo of the Napalm girl and say it changed things but the Vietnam War went on for three years after that. What do these pictures do? What good do they do? I’m asking myself that question. I thought those pictures that I took – that I risked my life for – would do something. They were meant to be seen by politicians, by decision-makers.

“I didn’t have to go to these places. I was the man who wanted to be there…who wanted to ram the pictures down your throat on a Sunday morning. Now when I think back at it I do not think it was worth the risk. I’m a terrible pessimist. I’ve come to think everything I did as a photographer was completely futile. I cannot allow myself to feel celebrated…not for any of those images.”

McCullin may be jaded today but he readily admits that he was fiercly ambitious as a young photographer and came to love the buzz of war. He is critical of how the military now controls the media in theatres of war but would still agree to be embedded with troops if that’s what it took to get a story. “I was very ambitious back then…I would have walked a tightrope – blindfolded – across Niagra to get into the Sunday Times,” he says. “I would have worked for nothing, despite the toll it was taking on my little family.

“Today we have the Iraq war and Afghanistan. And we’ve got this silly word ‘embedded’, which makes me think of taking your dog for a walk on a lead. You’re not even allowed to get close to anything like I did in Vietnam. The pictures I and others took then would be totally impossible now. But of course if I was a young photographer now I would still agree to go on an embed because I was so ambitious. Now I think the price is too high. There comes a time in life when you have to pull the plug on that. I was fortunate to be sacked by [then-Sunday Times editor] Andrew Neil – he allowed me to save my life and prevent my own destruction.”

Today McCullin’s photos are mostly brooding landscapes. While humans are absent you can, he says, see his whole soul poured into those images. “The thing they are not devoid of is emotion,” he says. “But there is still something disturbing in my landscapes, because there’s something quite dark in me. It would be stupid to think you could get away with 30 or 40 years of photographing wars and death and that once you finish all the bad dreams will be done and dusted. There may not be humans in my images but there is still danger in these fields. My pictures reflect something about me. And I print them dark because my thoughts are dark.

“There’s a battleground inside all of us I think. I have seen a lot of human suffering but that doesn’t mean I am a terrible miserable old man. I think I’m just surrounded by ghosts. I have been very lucky to survive really. I’ve been scavenging all my life – taking pictures of other people’s misery. And that hasn’t been easy.”