A Glasgow gangland boss and his associate have lost their appeal against jail sentences imposed for plotting to murder a man they believed was a police informer, after appeal judges ruled on Tuesday that the terms were not excessive.

David Nisbet, 36, and Declan McCuish, also 36, were given a total of 24 years in custody for conspiring to assassinate Ryan Carvil. Nisbet was jailed for 13 years and McCuish for 11 years, each with a further three years of supervision in the community on release. In a written judgment issued on Tuesday, the Court of Criminal Appeal in Edinburgh refused both appeals.

Lord Beckett, sitting with Lord Matthews and Lord Ericht, wrote that the court was not persuaded the sentences were excessive and that there was no miscarriage of justice. He wrote: 'We refuse the first appellant's appeal.' He added: 'The second appellant's appeal is refused.'

Nisbet conducted his own appeal

Nisbet appeared without a lawyer at the Court of Criminal Appeal late last month and told the judges that Lord Clark, who sentenced him in 2025, had imposed too harsh a term. He argued that people convicted of similar offences had received shorter sentences, and said: 'I would ask the court to reduce my sentence in the interests of justice.' He also told the court he wanted to conduct his own appeal, adding: 'I would prefer to get this over with.'

McCuish's lawyer, Mark Mohammed KC, argued that his client had played a lesser role in the conspiracy than others involved and should have received a shorter sentence, with greater differentiation between the two men. Lord Beckett rejected that argument, writing that it was unrealistic to expect mathematically calibrated precision when comparing sentences, given the variables involved, and that contrived complaints based on fine comparisons between co-accused would not find favour.

Lord Beckett also noted the care and courtesy with which Nisbet had presented his own case, while making clear that this did not change the outcome.

The plot uncovered through Encrochat

Nisbet and McCuish had denied conspiring to murder Carvil between 23 March and 14 April 2020, but were found guilty of the offence at addresses in Glasgow, Lenzie in East Dunbartonshire, and Liverpool. They were caught after messages on the encrypted Encrochat communications network revealed their involvement in the plan.

During the plot they identified the address where Carvil was living, the car he was using, and monitored his movements. They offered money and arranged for hitman James Richards to be brought to Glasgow from Liverpool to carry out the murder, but Richards later got cold feet and did not carry out the killing. The pair also obtained stolen cars with false number plates to be used in the crime and made plans to conceal the gun and set fire to the car used in the murder.

Prosecutor Lindsey Dalziel told the original trial that Nisbet was calling the shots and believed Carvil was a grass. She said Nisbet had entered into discussions with no fewer than three potential hitmen, and that the pair sought to turn the streets of Glasgow into a warzone. Nisbet used the handle Las Diablo in his messages, and in one text to a potential assassin he discussed testing a new gun before passing it on.

Drugs, a handgun and other sentences

Nisbet was also convicted of directing others to commit serious offences between March and June 2020, instructing them to obtain, transport, adulterate and supply cocaine, heroin and etizolam, and to transfer cash from drug dealing, as well as possessing a handgun to commit acts of violence. McCuish was convicted of being involved in serious organised crime in March and April 2020 by being concerned in the supply of benzodiazepines.

The sentencing judge had told Nisbet that the Encrochat messages revealed an alarming level of commitment to having the victim murdered, and pointed out that Nisbet had also been found with a handgun in his possession.

Richards was later given seven and a half years by Judge Lord Young for his role in the conspiracy. Another member of the group, Anthony Connell, was given six years and nine months by Judge Lord Scott at the High Court in Glasgow in February 2026.