Charlotte was stabbed through the heart

Beatriz Martins-Paes, 18, told the Old Bailey she did not realise she had "done damage" when she attacked Charlotte Polius in April 2004.

Charlotte, 15, was stabbed at a house in Saxon Road, Ilford, east London, in an alleged confrontation.

Miss Martins-Paes, from Brentwood, Essex, admits manslaughter but denies murdering Charlotte.

'It was unreal'

Giving evidence the defendant, who was 17 at the time, said: "I did not think I had caused something bad. I know it does not make sense but it is true.

"I cannot explain it. It was all unreal. I did not believe it happened. It was just, like, shocking."

Charlotte, of Carroll Close, Stratford, east London, was attacked during an alleged confrontation with Miss Martins-Paes after an incident on the dance floor.

Miss Martins-Paes said she had gone upstairs to find out what the problem was.

It was just really quick Beatriz Martins-Paes

"She said I was too rude, I said 'You are nasty to me'."

She told the court that she could not remember deciding to take out the knife.

"It was just really quick. The bag was open."

When asked whether she recalled stabbing Charlotte, she replied: "No. I try not to. I know it happened."

She also denied witnesses' allegations that she had turned away and said "I will shank her again."

The case continues.