Lord Tom King was Defence Secretary during the 1990-1991 conflict in the Gulf, overseeing the largest single deployment of British troops since the Second World War.
This year marks the 30th anniversary of the First Gulf War, where a US-led coalition sought to expel Saddam Hussein's forces from Kuwait.
After the Cold War ended in 1990, many questioned the need to retain such fighting power.
Lord King said: "People thought: 'Well, we're going to have a peaceful world now,' and it suddenly seemed that we didn't need anything like the defences that we had.
"When I announced the programme for some reductions in the Army, the Navy and the Air Force at that time, the challenge that I got was 'Why on earth are we keeping so many people in uniform? What are they for? What threat do we really face?'.
"I had rather luckily said: 'Well, it's the threat of the unexpected', and three days later, the unexpected happened."
On 2 August 1990, Saddam Hussein ordered Iraqi forces to march on oil-rich Kuwait.
British Prime Minister Margaret Thatcher was in the US with President George H W Bush at the time.
Lord King described them as "bluntly, the only two people in the world really, with the resources and determination to take some action pretty quickly".
He said they had "agreed that they would act, and we got moving".
"It was a very challenging time but, of course, it's what the Ministry of Defence is there for, he added.
The Ministry of Defence quickly moved to working around the clock, arranging deployments, making decisions and providing resources for what was expected to be a costly conflict.
"There was a risk of quite substantial casualties – [Saddam Hussein] had already used chemical weapons against his own people," Lord King said.
Lord King wanted to ensure troops had the right kit for a war against Iraq, but one of the first problems was a lack of desert uniforms.
Ironically, a substantial number of them had been sold to the Iraqis a few years earlier, as officials had thought desert warfare was consigned to the past.
"I rang up the chairman of Marks & Spencer and I said: 'We've found that we're 7,000 short of trousers...' and I said: 'Where do you go for trousers?'.
"He gave me some good advice... and in not much more than a week, we had 7,000 pairs of desert uniform trousers."
In the months between Iraq's invasion of Kuwait and the start of the war, the world's media descended.
The conflict saw on-the-day reporting of events like never before.
"It was the first TV war," Lord King said.
"It coincided with the launch of CNN 24-hour news and also because of the interest we had – this sudden major event taking place – we had massive TV press and reporters coming out... all wanting to be there and involved.
"We then had the problem of keeping communications going and keeping public relations going as well – and confidence in what we were doing."
With the war approaching, Margaret Thatcher resigned as prime minister and on 28 November John Major took over.
On 16 and 17 January 1991, an air campaign was launched against Iraq.
As part of our look back on the First Gulf War 30 years later, Sir John Major told Forces News the conflict was on his mind "every waking moment".
The land campaign that followed on 24 February was over so quickly that US General Colin Powell called it "the 100 hours war".
"The land campaign was made possible because there had been six weeks of a brilliant air campaign which had pretty seriously damaged Iraqi positions and resources," Lord King said.
"In my judgement, we stopped 24 hours too soon.
"George Bush was so relieved that we hadn't had the huge number of casualties warned, that he called it a day.
"If we'd gone on another 24 hours, the left foot would have got round a bit further and 1 Republican Guard Division certainly would have been trapped.
"They were the key, they were the core of Saddam's army... and proved to be pretty punishing for the Kurds and for the Shia and the Marsh Arabs and others who tried to rise up afterwards."
A ceasefire was declared on 28 February 1991, ending the First Gulf War.
Listen to the story of the First Gulf War, told by those who were there. Decision-makers, military commanders, soldiers, sailors and air personnel reflect on their roles in the conflict, 30 years on.
'GRANBY: The Storm in the Desert' is available wherever you get your podcasts and on bfbs.com/podcasts.