In January 1991, the UK was part of a 39-nation coalition that went to war with Iraq.
It was to be one of the first major tests for Sir John Major, who had just become Prime Minister following Margaret Thatcher's resignation.
Saddam Hussein had ordered his troops to invade Kuwait on 2 August 1990 and the small oil-rich state was easily overwhelmed by the dictator's superior force.
When diplomatic efforts to solve the crisis were abandoned, the UN Security Council set a deadline of 15 January 1991 for all Iraqi forces to be withdrawn and authorised the use of "all necessary means" to force Iraq to comply.
Speaking to Forces News, Sir John said: "War should be the last resort, not the first resort because people are going to be injured and, in some cases, killed.
"It does consume an extraordinary amount of time when you prepare for something like this.
"Your whole focus is on it, you don't suddenly have a meeting for an hour on Tuesday morning and then go away and forget it, despite other issues," he added.
"It is actually in your mind every waking moment, and sometimes when you are asleep as well, frankly."
Hussein failed to respond, so allied forces – who were already poised and in position – were ordered to initiate combat operations against Iraqi forces.
The first phase of the Gulf War was the extensive aerial bombing campaign from 17 January to 23 February 1991.
More than 100,000 sorties were flown by the coalition, dropping 88,500 tons of bombs and widely destroying military and civilian infrastructure.
Each day, the bombing would begin at midnight UK time.
"I think I was up every night 'til two, three o'clock in the morning to see how it was going and then back up awake again at 6 o'clock to see how it had gone," Sir John remembers.
"Some of my senior civil servants were up all night, night after night after night.
"I think we are very conscious that older men and women send younger men and women to war.
"We may have to make the decision to go, but they bear the risk of being seriously injured, perhaps for life, or not returning at all.
"And yes, that does weigh on the mind, it can't not do so."
After a six-week air campaign destroying strategic targets, it was on Sunday 24 February 1991 that coalition ground forces were given the green light to advance.
Fighting was over in less than 100 hours.
On 28 February, US President George W. H. Bush declared a ceasefire.
Sir John then made a final visit to the troops in the Gulf, where he famously told them "you'll be home soon".
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 from Friday 15 January, wherever you get your podcasts and on bfbs.com/podcasts.