The deployment of troops to the Gulf continued on Wednesday morning with the departure of 600 troops on three flights from RAF Brize Norton in Oxfordshire.
A member of 16 Air Assault Brigade prepares to leave for the Gulf
The troops, members of the 16 Air Assault Brigade, included paratroopers, infantry and support units.
A further two flights will leave on Thursday, each containing 180 troops, bringing the total number to have left the air base to just under 1,000.
Some of those who left spoke of their concern at the recent public outcry over any war with Iraq.
Lack of support
In his monthly press conference Prime Minister Tony Blair said he "should and does listen to the thousands that marched on Saturday" in anti-war protests.
Speaking on Tuesday he insisted most of the marchers were not against war in all circumstances but were opposed to a war that was "rushed or unnecessary".
"There is no rush to war," he stressed.
The personnel who left on Wednesday are part of a total deployment of around 40,000 British troops to take part in possible action against Iraq.
The troops, mainly from the 3rd Battalion the Parachute Regiment, based in Colchester, are among the last expected to be deployed to the Gulf region.
The last group to leave were 180 members from three regiments of the army air corps, who will give air cover to ground troops.
The BBC's Jane O'Brien, who talked to members of the 16 Air Assault Brigade before they flew out, said many were aware of the anti-war feeling in the UK.
"Officially morale is high, but unofficially a lot are concerned about the lack of public support," she said.
Saturday's anti-war march in London attracted an estimated 750,000 to two million people.
Many of the paratroopers leaving for the Gulf were also apprehensive about a possible war, with most concerned about the threat posed by chemical, biological or nuclear weapons.
Private Daniel Tearle, 20, of Leighton Buzzard, Bucks, said he was trying not to think about it, but admitted the potential risks were "scary".
"I am scared and worried. Everybody is worried about what might happen, but it is what we are trained to do, it is our job," he said.
Lieutenant Danny Read, 28, from Portishead, Somerset, said the troops were aware of public opposition to military action, but were trying not to let the publicity affect their morale.
"I would prefer more support from the public, but we support ourselves and each other," he said.
Captain Tanya Gutheridge, of the 16 Air Assault Brigade told BBC News 24 personnel were kept motivated and fit and trained for war combat.
Many of the troops slept on their rucksacks as they waited to board the flight, which left shortly before 0700 GMT.
A spokeswoman for the Ministry of Defence refused to confirm exactly where in the Gulf the troops would be landing.
The movement of troops to the Gulf is the biggest deployment of troops since the 1950s.
Conservative defence spokesman Bernard Jenkin said although his party supported the sending of troops to the Gulf it was concerned at the "serious over-commitment of British forces".
Speaking on BBC Radio 4's Today programme, he said: "If it is going to go on for more than a few months it is going to completely wreck...the training and readiness cycle of...all three armed forces.
"Unless you have time to train and rest you undermine your combat effectiveness," he added.