A grieving widower has called for new laws to tackle "irresponsible and reckless" cyclists after a former courier was convicted of knocking down and killing his wife while riding an illegal bike.

Charlie Alliston, then 18, was travelling at 18mph on a fixed-wheel track bike with no front brakes before he crashed into 44-year-old Lewisham mum Kim Briggs as she crossed a busy street in London in February last year.

Prosecutors took the unprecedented step of bringing a manslaughter charge due to the unusually grave circumstances of the case.

Jurors took more than 12 hours to find Alliston not guilty of manslaughter yesterday, Thursday August 23, but convicted him of a lesser offence of causing bodily harm by wanton and furious driving under the 1861 Offences Against the Person Act, which carries a maximum sentence of two years in jail.

Judge Wendy Joseph QC said she was considering a prison sentence, and added: "I have not seen one iota of remorse from Mr Alliston at all, at any stage."

She adjourned sentencing until September 18.

Outside court, Mrs Briggs' widower Matthew, who together have a daughter aged 11 and a son aged 14, called for a "radical change" in cycling culture and the introduction of new laws, including causing death by dangerous cycling.

He said: "I am now determined to do what I can to prevent others from going through the heartache we have had to bear following Kim's needless death.

"We need to radically change some aspects of our cycling culture.

"This is not a witch hunt against all cyclists, I, myself cycle in London, only the irresponsible and reckless.

"We all have to share these imperfect streets, let's do so with care and due regard for each other.

"The current law is outdated and has not kept pace with the huge increase in the number of people cycling and the associated increased risk of collisions, nor the attitude of some cyclists.

"I am calling for an introduction of laws of causing death or serious injury by dangerous or careless cycling, thereby bringing cycling laws into line with the Road Traffic Act."

The Old Bailey had heard how Alliston, of Trothy Road in Bermondsey, had been on his way to buy food for his girlfriend when he crashed into Mrs Briggs during her lunch break.

As she crossed the capital's Old Street, he twice shouted for her to get out of the way but failed to stop or avoid the head-on collision.

He sprang up and continued to shout at his victim as she lay in the road with catastrophic head injuries.

Mrs Briggs died in hospital a week later.