The 22-year-old was manning a machine gun at the checkpoint at about 06:45 local time (03:15 BST) when up to ten Taliban fighters attacked.
Nato's International Security Assistance Force (Isaf) supported the British soldiers by firing at the Taliban's firing line, but by this point the Newcastle-upon-Tyne-born Guardsman Davison had already sustained a gunshot wound.
He was flown to the principal British base in the area – Camp Bastion – but neither medical teams in the helicopter or the camp itself were able to save him.
Guardsman Davison, who leaves behind his mother Maureen Hindmarch, father Ray Davison and sister Caroline, had joined the army two summers ago.
His commanding officer Lieutenant Colonel Carew Hatherley said that the young guardsman had "always wanted to be a soldier".
"As a grenadier he was immensely proud of the uniform he wore, be it tunic and bearskin or combats," he said.
"He died fighting to protect other grenadiers and gave his life in doing so. There is a no more selfless act a soldier can perform. Guardsman Davison was a popular soldier who will be sorely missed and never forgotten," Lt Col Hatherley added.
Guardsman Thomas Eyre, who served in Afghanistan alongside Guardsman Davison, described his friend as someone who "always stuck up for his mates and looked after them".
"He went down defending his section, which was how he lived, sticking up for his mates," the soldier continued. "I and all his friends will miss and think of him always.
"It brings back an old saying that there is 'no greater love as a man, than to lay down his life for his friends'."
Defence secretary Des Browne said he was "deeply saddened" by the guardsman's death.
"My thoughts are with his family, friends and his comrades in Afghanistan as they struggle to come to terms with their loss," the minister stated.
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