Prince William paid tribute last night to a close female friend who was among four British soldiers killed in Iraq by a bomb.

Joanna Yorke Dyer, 24, an Oxford graduate, was in the same company as Prince William at Sandhurst. Clarence House released a statement that said: “Prince William was deeply saddened to hear the tragic news of Jo Dyer’s death. Jo was a close friend of his at Sandhurst and he is very much thinking of her family and friends, and they will remain in his thoughts and prayers.”

Second Lieutenant Dyer, from Yeovil, who was with the Intelligence Corps attached to the 2nd Battalion The Duke of Lancaster’s Regiment, was one of four personnel who died in Basra on Thursday. The others were Kingsman Adam James Smith, who was with the same battalion, and Corporal Kris O’Neill and Private Eleanor Dlugosz, who were from the Royal Army Medical Corps, responsible for accompanying patrols into the city and providing them with medical support. All four were described yesterday as bright and dedicated young soldiers.

A Kuwaiti civilian interpreter was the fifth victim of the deadliest attack on British troops in months. The ambush occurred on an armoured column returning from a late-night routine operation to seize a rebel arms cache in the city, a hotbed of militias, tribes and oil-smuggling mafia.

Kingsman Smith’s family released a tribute to the 19-year-old soldier, labelling him “Adam, our hero, our star”. They said that he had “everything to live for”.

“We keep thinking, hoping, it’s not real and at any moment we will wake up from this nightmare. Adam was the most wonderful and beautiful person anyone could wish to meet,” they said.

Second Lieutenant Dyer graduated in PPE at Oxford before beginning officer training at Sandhurst. Her father, Lieutenant-Colonel Neil Dyer, formerly of the Royal Army Ordnance Corps, was a contemporary at Sandhurst of Captain Mark Phillips, the Princess Royal’s former husband, and her mother, Annie, was a captain in Queen Alexandra’s Royal Army Nursing Corps. It was reported last night that her sister, Holly, is also serving with the Intelligence Corps in Iraq but was at home on leave.

Second Lieutenant Dyer’s commanding officer, Lieutenant-Colonel Mark Kenyon, described her as a talented and energetic officer. Friends and colleagues said that she would be remembered “as the girl who could light up a room”.

The other female casualty had returned to the war zone for the second time only weeks ago. Private Dlugosz, 19, from Southampton, was deployed to Iraq last November before returning to Britain in January to complete a course for medics. She was sent back to Iraq last month. Her commanding Officer, Lieutenant-Colonel Martin Toney, said that Private Dlugosz, known as Ella or DZ, had displayed “guts and determination”. Private Stella Lee, her friend and colleague, said: “Helping others before herself was who she was.”

Corporal O’Neill, 27, who was married with two sons, was involved in teaching first aid to the Iraqi police. His friend and colleague Corporal Martin Blaker-Hood said: “Kris was hard-working and very well respected. He loved his family and was a really good bloke. His death is a big loss.”

His Squadron Commander, Major Phil Carter, said: “He was dedicated to ensuring that the soldiers we support receive the best possible medical care and his death is a tragedy.”

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