Thirteen people have been jailed for a total of nearly 15 years for offences relating to an "unprecedented" Halloween 'ride out' which caused chaos last year in Leeds.
A large number of motorbikes congregated and were ridden dangerously and anti-socially through the city centre and surrounding areas on October 31.
And today, twelve men and a woman were sentenced at Leeds Crown Court after earlier pleading guilty to causing a public nuisance.
They were arrested as part of Operation Dice, an investigation led by Leeds District CID, following the 'ride out', where motorbikes and quad bikes congregated in Kirkstall Road before a large number were ridden through the city centre en masse, including through pedestrian areas and shopping arcades.
Chief Superintendent Paul Money, Leeds District Commander, said: "The behaviour of these individuals and others that night put people's safety at risk, caused unnecessary fear to the public and created an image of lawlessness in the heart of the city that we simply could not allow to go unchallenged.
"We made it very clear in the immediate aftermath of the incident that we would be taking firm action against all those we could identify as being involved, and these outcomes at court today show us delivering on that promise.
"The situation this group created that night was completely unprecedented in Leeds and West Yorkshire and it presented a significant challenge to us due to the large number of people involved and the limited tactical options available to safely stop people on motorbikes."
The police investigation included detailed analysis of CCTV from a range of sources to identify suspects and their vehicles.
Public appeals for information and extensive enquiries, including social media, also supported the investigation.
A series of early morning raids at addresses across Leeds in December last year resulted in the arrests of the main suspects and saw a number of motorbikes seized, police said.
At today's hearing the defendants were each jailed for a minimum of 12 months.
Chf Supt Money added: "We immediately launched a criminal investigation into the incident which brought a number of arrests and seizures of vehicles over the following weeks and ultimately led to the convictions we have seen today.
"We also learned from the experience and now have comprehensive plans in place at both force and district level to tackle any such events in future. These proactive tactics have seen us head off a number of other ride out events before they could materialise on the ground and our approach has been used nationally as best practice for policing such events.
He said he hoped today's sentencing would now deter any copycats in the future.
Following the ride out, Leeds City Council secured a landmark injunction, under Section 1 of the Anti-Social Behaviour, Crime and Policing Act 2014, which bans anyone from participating in anti-social driving of motor vehicles, including motorbikes and quad bikes, involving two or more motor vehicles in any public place in the Leeds district.
The full order, which carries a power of arrest, was granted for five years at Leeds County Court in January.
The order also forbids people from promoting, organising or publicising the anti-social driving of motor vehicles.
Police also foiled two similar potential 'ride out' events planned for Leeds on December 11 and New Year's Eve last year.
According to West Yorkshire Police, following today's sentencing:
David Armitage, 26, of Brookfield Road, Headingley was jailed for two years. Jamie Ayres, 26, of Lupton Avenue, Burmantofts was jailed for 12 months.
Omar Ahmed, 24, of Stonegate View, Meanwood was jailed for 12 months. Ashley Benson, 25, of Whingate Road, Armley was jailed for 12 months.
Michael Clough, 27, of Torre View, Burmantofts was jailed for 14 months. Ben Colley, 26, of Butterbowl Road, Farnley was jailed for 14 months.
Dean Fawcett, 28, of Intake View, Middleton was jailed for 12 months. Nicholas Flaherty, 29, of Prospect Street, Farsley, was jailed for 18 months.
Rachel Taylor, 29, of Nowell Lane, Harehills was jailed for 12 months. Joshua Hawley, 22, of Mead Grove, Colton was jailed for 12 months.
Dylan Lockwood, 23, of Torre Grove, Burmantofts was jailed for 12 months. Adam Nicholson, 26, of Henley Terrace, Bramley was jailed for 12 months.
Anton Rojas, 26, of Skelton Avenue, Burmantofts was jailed for 12 months.Ben Colley was also convicted of driving while disqualified and without insurance.
Nicholas Flaherty was also convicted of perverting the course of justice.