A police officer who was jailed but then cleared on appeal of throwing a woman head-first on to the concrete floor of a cell was sacked by his force today. Sergeant Mark Andrews was caught on CCTV dragging Pamela Somerville, 59, across the floor of Melksham police station in Wiltshire before shoving her into a cell.

The former soldier, who remained suspended on full pay, was sacked by Wiltshire police following an internal conduct hearing, which was held in private. The officer was jailed for six months in September by a district judge at Oxford magistrates court, who condemned him for abusing a position of trust. Andrews spent six days behind bars before he was released on bail pending an appeal.

Last month at Oxford Crown Court a judge quashed his conviction and sentence for assault causing actual bodily harm. Mr Justice Bean said after the four-day hearing that he was satisfied Andrews did not intend to throw Ms Somerville into the cell and that injuries she suffered were probably caused by her falling to the floor after letting go of the door frame.

Somerville needed stitches to a gash above her eye following the incident in July 2008. She had been detained for failing to provide a sample for a breath test after being found asleep in her car. She denied any wrongdoing, and charges were later dropped because of insufficient evidence.

Andrews told the appeal hearing that Somerville was the most unpredictable prisoner he had ever come across; she had been abusive to both him and his colleagues. The court was shown CCTV footage in which he was seen apparently throwing her on to the cell floor. A minute later she staggered to her feet with injuries to her face and eye.

"I don't think I did anything wrong," Andrews told the court. "She had been holding on to the cell door frame when she suddenly let go. It was like pulling a cork out of a bottle."

Andrews, who is married with children aged four and two, joined Wiltshire Police eight years ago and was promoted to sergeant in 2005. Before joining the force he spent nine years in the army, reaching the rank of sergeant.

Pat Geenty, assistant chief constable of Wiltshire police, said that while Andrews's conduct was not criminal, it "fell well below the standards expected".

In a statement, he said: "At the appeal Mr Justice Bean concluded that the injury to Pamela Somerville was not intentional and was not as a result of criminal action by Sgt Andrews.

"Whilst respecting that decision, our concern was such that it was felt appropriate to independently examine whether any police conduct breaches had occurred …

"The conduct hearing … has reached a decision that Sgt Andrews should be dismissed from the force and this will take place with immediate effect.

"We have always accepted that Pamela Somerville was injured whilst in our care and I want to apologise again to her for the way she was treated …

"We acknowledge that there has been substantial media coverage and public interest in this case and that the images on the custody CCTV will have had an impact on the force and those who work within it.

"The criminal appeal hearing concluded that Pamela Somerville had been lawfully arrested, was intoxicated, very unco-operative, verbally abusive, and disruptive to the processes which the law required the police to carry out. Nevertheless, this conduct hearing has concluded that Sgt Andrews actions, whilst not criminal, fell well below the standards expected.

"I hope that this decision will be of comfort to Pamela Somerville who was injured whilst in our care and I want to emphasise that she had not committed any crime.

"The public can be reassured that their safety remains our top priority and we will learn any lessons that need to be learnt to reduce the chance of any such future incident."