Brothers Raja Hussain and Jonaade Hussain, and Sahrear Islam-Miah were part of a gang which attempted to intimidate jury members as they left Leeds Crown Court during a trial in 2017.
A fire alarm in the court building was deliberately set off and jurors were filmed by gang members as they gathered at an assembly point outside.
Another juror was also followed through Leeds city centre and ran into a bar to ask for help after being followed one of the conspirators.
Law student Islam-Miah was found guilty of conspiracy to pervert the course of justice.
Jonaade - a qualified solicitor - and his brother pleaded guilty to the offence.
The Hussain brothers were also convicted of firearms and explosives offences at a separate trial during 2017.
Raja, 33, was sentenced to a total of 30 years in jail.
Jonaade, 29, was jailed for 15 years and Islam-Miah, 29, received a six-year sentence.
The Court of Appeal have confirmed applications made for leave to appeal against convictions and sentences for all three defendants were rejected earlier this month.
The jury tampering offences took place in February 2017 during a manslaughter trial over the death of 88-year-old great grandmother Betty Laird.
Mrs Laird died during a 'crash-for-cash' scam that went disastrously wrong.She suffered fatal injuries when the Renault Kangoo she was a passenger in was struck on Old Lane, Beeston.
A VW Passat was driven into the side of the Kangoo in order to make fraudulent injury compensation claims from insurance companies.
Mrs Laird was in the vehicle with her friend Jeff Grimshaw, 77, at the time of the incident.
She suffered multiple injuries in the collision and died that evening.
Mr Grimshaw died later of causes that could not be proven to have been connected to the collision.
The court heard there was evidence that the defendants in the trial were involved in an organised crime network specialising in making fraudulent crash injury claims.
The attempts to interfere with the jury began on February 20, 2017, with the deliberate setting off of the fire alarm on the day Mr Justice Goss summed up the case after the court heard two weeks of evidence.
The following day - after the jury had been sent out to deliberate - approaches were made to jury members as they left the court building for the day.
Mr Justice Goss later took the highly unusual step of dismissing the jury.He then took advantage of rarely-used legal powers which allowed him to continue to hear the case without a jury.
In a separate trial, the Hussain brothers were sentenced over a 'deadly armoury' of guns and explosives which was uncovered by police at an industrial unit.The pair were found guilty of possessing firearms and explosives.
West Yorkshire Police made the discovery at Bad Boy Motors, in Hunslet.
During May and June 2015 police received reports of more than 100 gang-related offences including arson, criminal damage and violence within a square mile of the Beeston area.
The incidents culminated in an attempted murder of a man who was shot in October 2015.
Suspects were arrested over the incident and police received information following the shooting which led them to Bad Boy Motors, on Leathley Road.
Officers carried out an extensive search of the property on November 26, 2015, and discovered a large amount of gunpowder obtained from powerful fireworks.
Three shotguns, two handguns and ammunition were also recovered from a gated off area to the rear of the premises which was guarded by a pit bull terrier dog.
West Yorkshire Police made an application to the Attorney General for permission to charge the pair with offences under the rarely-used Explosives Act.
Both men were found guilty of unlawful possession of explosives, three offences of possession of a prohibited firearm, possessing a firearm and a shotgun without a certificate, possessing ammunition without a certificate and perverting the course of justice.
The pair claimed throughout the trial that the weapons, ammunition and gunpowder had been planted at the premises by others.
Jonaade Hussain's barrister, Abba Lakha, QC, said his client was a former Leeds Grammar School pupil who had done on to study law and computing at Huddersfield University.
Mr Lakha said Jonaade then obtained a contract as a trainee solicitor in Manchester but gave the profession up, in 2014, after just eight months.
The lawyer said: "His fall from grace has been spectacular."