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 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.

Charlie Alliston was cleared of manslaughterCharlie Alliston was cleared of manslaughter (John Stillwell/PA)

Jurors took more than 12 hours to find Alliston not guilty of manslaughter 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.”

Outside court, Mrs Briggs’ widower Matthew called for a “radical change” in cycling culture and the introduction of new laws, including causing death by dangerous cycling.

Kim Briggs Kim Briggs “was quick to smile, slow to judge and even slower to anger” (Metropolitan Police/PA)

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 The current law is outdated and has not kept pace with the huge increase in the number of people cycling and the associated increased risk of collisions, nor the attitude of some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

“We need to change the way the law deals with this. 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.”

Widower Matthew Briggs sat in court throughout the trialWidower Matthew Briggs sat in court throughout the trial (Nick Ansell/PA)

The Old Bailey had heard how Alliston, wearing a top with Anti Social on it, 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.

Alliston criticised Mrs Briggs and claimed she was responsible for the crash in a string of posts on social media in the days that followed.

Charlie Alliston was convicted of Charlie Alliston was convicted of “wanton and furious driving” (Lauren Hurley/PA)

Jurors heard Alliston’s trendy “fixie” bike was not legal to use on the road without being modified to add a front brake. He bought the £700 Planet X bike second-hand for £470 in January last year, telling the vendor he wanted to use it for track cycling.

Crash investigators who studied CCTV of the incident concluded Alliston would have been able to stop and avoid the collision if the bike had been fitted with a front brake.

But giving evidence in his trial, Alliston, now 20, from Bermondsey, south London, claimed not to know the bike was illegal on the road and told jurors he was not riding recklessly.

He said: “At all times I would know what I’m doing and completely responsible for my actions. I did not get a kick or enjoyment out of not being safe.”

Matthew Briggs speaks to the media outside the Old BaileyMatthew Briggs speaks to the media outside the Old Bailey (Dominic Lipinski/PA)

Mr Briggs, from Lewisham, south London, sat in court throughout the trial, during which the CCTV footage of the crash was played several times.

In a statement read in court, he paid tribute to his “wonderful” wife, saying: “She was quick to smile, slow to judge and even slower to anger.”

Duncan Dollimore, of Cycling UK, said: “Riding a fixed wheel bicycle on busy roads without a front brake is illegal, stupid, and endangers other road users especially pedestrians.”