Personnel, veterans and members of the public have paid their respects to the British personnel who lost their lives on Operation Telic in Iraq.
On 20 March 2003, US and allied forces invaded Iraq to remove Saddam Hussein's regime which was believed to be possessing weapons of mass destruction - a claim which was later disproved.
The UK's involvement in the war was codenamed Operation Telic and resulted in the deaths of 179 British service personnel.
To mark 20 years since the start of Operation Telic, the Ministry of Defence (MOD) has remembered the British personnel who didn't return from operation.
Defence Secretary Ben Wallace said: "Marking 20 years since the start of Operation Telic, we remember the 179 British personnel who lost their lives and pay tribute to them and their families.
"We remain committed to the close and enduring partnership the UK and Iraq have today, working together to address shared global security challenges."
Veterans' affairs minister Johnny Mercer, a former soldier who served from the tactical to the strategic level throughout a career across the globe, including multiple combat operations, paid tribute to families and veterans in a post to Twitter.
The former Army captain said: "UK Forces began combat operations in Iraq today 10 years ago. I pay tribute to their professionalism, courage and duty.
"I particularly remember all those families and veterans for whom life was never the same again – especially from my regiment."
Retired Royal Air Force navigator John Nichol, who was shot down over Iraqi territory on the first day of the First Gulf War, then later brutally interrogated before appearing on Iraqi television shared his thoughts on social media.
He said: "Iraq was invaded to depose Saddam Hussein, retrieve "weapons of mass destruction" & make the region/world safer.
"Catastrophically bad political/military decisions cost trillions $, 100,000s lives & ensured the region/world is more dangerous. RIP those who gave all."
Across the armed forces community, memories have been shared to honour the fallen and remember the key date.