Spain’s supreme court has jailed the former transport minister José Luis Ábalos for 24 years for taking bribes on public contracts for sanitary equipment such as ‌face masks during the Covid pandemic.

Ábalos’s aide, Koldo García, was jailed for 19 years in a trial that is one of several scandals to have enveloped the government of Pedro Sánchez over recent months.

The case is seen as particularly damaging for Sánchez because Ábalos was his trusted right-hand man for many years.

Ábalos and Koldo heard the sentencing via video-conference in the Madrid prison where they have both been held in preventive custody since November.

Presided over by seven judges, the court heard evidence from public officials, civil servants, expert witnesses and police, and found Ábalos and García guilty of being part of a criminal organisation, bribery, misuse of public funds, money laundering and influence peddling.

The court concluded that “the seriousness of the charges derives from the fact that they erode the fundamentals of a democratic state and distort the purpose of public power into an instrument at the service of individual interests”.

The sentencing comes two days after a separate court ruled that Sánchez’s wife, Begoña Gómez, who faces corruption and influence-peddling charges, is a flight risk and must hand over her passport.

Gómez is awaiting trial over accusations she used her influence as the prime minister’s wife to secure sponsors for a university master’s degree course she ran, and that she used state funds to pay her assistant for help with personal matters. The case was triggered by a complaint from the rightwing pressure group Manos Limpias, which translates as Clean Hands.

Gómez lives in the Moncloa palace, which is the seat of government and probably one of the most secure buildings in Spain, but the judge Juan Carlos Peinado said members of her security detail might help her to escape.

This in turn has led Spain’s judicial watchdog, the General Council for Judicial Power, to take disciplinary action against Peinado for the “serious offence” of impugning the integrity of public servants, in this case, Gómez’s personal protection agents.

Spain’s national police also released a rare statement calling the judge’s reasoning unjustified and stressing the force’s political neutrality.

The government has denounced Peinado for what it described as his obsession with Gómez who, even if found guilty, would apparently have derived no personal benefit from the alleged influence peddling.

Sánchez has not been named in any of the ‌cases, but his brother, David, is on trial over allegations that he was handed a bespoke job by the Socialist-led council of the south-western town of Badajoz in July 2017, when his brother was the national leader of the party but not yet prime minister.

Gómez and David Sánchez have denied any wrongdoing, and the prime minister has said his family have been the victims of a harassment and bullying operation.

The case against David Sánchez was also brought by Manos Limpias, leading many to believe there has been a concerted effort by rightwing forces to damage the Sánchez government.

So-called “lawfare” has become increasingly common in Spain, where the courts are obliged to consider cases brought by private organisations or individuals, however frivolous the charge might initially appear.

During her eight years in office, Barcelona’s leftwing mayor Ada Colau faced 22 legal challenges to her policies, every one of which was eventually dismissed.

Ábalos is the fifth government minister to be jailed since Spain’s transition to democracy in 1978.

Víctor de Aldama, a businessman linked to the scandal was also jailed for four and half years on Monday, but his sentence was suspended because he had cooperated with the court. Nor will he have to hand back the €3.7m (£3.2m) he received in commissions over the procurement of masks.