Jurors have begun their deliberations to decide the fate of a young cyclist accused of killing a Lewisham mum after ploughing into her on a bike.

Former courier Charlie Alliston was 18 years old when he hit Kim Briggs as she crossed Old Street, east London, on February 12 last year.

The 44-year-old HR consultant, who had been on her lunch break, suffered "catastrophic" injuries when the pair clashed heads and she died in hospital a week later.

In a legal first, Alliston, now 20, is accused of the manslaughter of Mrs Briggs and of causing bodily harm by "wanton or furious driving", a charge he denies.

Alliston, of Trothy Road in Bermondsey, said he was not aware that the ‘fixie’ bike he was riding with no front brake was not legal.

Prosecutors say the collision could have been avoided had a front brake been fitted, while the defendant told the jury having it brake "wouldn't have made a difference" because he would not have had time to pull it.

Judge Wendy Joseph QC, in summing up to the jury at the Old Bailey, said a police expert estimated Alliston was doing between 10 and 14 miles per hour just moments before the crash, which was captured on CCTV.

One witness, David Callan, told jurors he heard Alliston shout something as Mrs Briggs lay on the ground.

In his closing speech before the jury was sent out, Mark Wyeth QC, defending, questioned the manslaughter charge.

He said: “The counsel of perfection that the prosecution put forward is so complete, if you reversed the outcome, if Mr Alliston went over the handlebars, had fractured his skull and died and Mrs Briggs got up and dusted herself off, what's to stop her from being prosecuted for manslaughter on the approach the prosecution take, because she should not have been there?"

He said Mrs Briggs had not used the pedestrian crossing 30 feet away from where the pair collided and Alliston had right of way.

"This is not a case of somebody jumping the lights," he said.

"This is not a case of an approach speed on this bike that was illegal, it's a 30mph area and the hazards that were in that road were not of Mr Alliston's making."

Mr Wyeth also accused prosecutors of failing to pay attention to his client's claim that Mrs Briggs stepped back slightly and put herself in the way of his bike.

He said: "The crown have run with this no brake point without, you may think, a proper analysis of the stepping back point.

"Their preoccupation with brakes and speed is in contrast with what the defendant was saying, which was really about the position of Mrs Briggs and she was, in due respect, the hazard."