The Serious Fraud Office’s reputation for legal competence is under scrutiny following the latest setback to a high-profile prosecution.

A Crown Court judge last week refused to let the office amend an indictment on criminal offences relating to contested allegations of anti-competitive behaviour over the supply of drugs to the NHS.

He ruled that subject to appeal the indictment would be quashed.

The office said it would seek leave to appeal.

Last week’s hearing, in front of Mr Justice Pitchford at Southwark Crown Court, is subject to reporting restrictions. However Goldshield, one of five defendant pharmaceutical companies and eight defendant individuals, was granted permission to make a market announcement.

Goldshield claims the case cost taxpayers £40m, which it described as ‘an appalling waste of money for the taxpayer’.

A spokesman for the SFO said: ‘It is our position that it was correct for us to bring these proceedings.’