HUNDREDS of files relating to contaminated blood were removed by government officials and went missing in a possible “cover-up,” it has emerged.

Following the start of the infected blood inquiry last year, a Government Internal Audit Agency (GIAA) investigation found that around 950 files relating to blood policy had been “checked out” by staff going back years.

The report has been released to campaigner Jason Evans, whose father died in 1993 having contracted hepatitis and HIV.

Suing the government for negligence, Mr Evans said the removal of documents “probably goes back decades” and could form part of a government cover-up.

The contaminated blood scandal, where thousands of patients were infected with HIV and hepatitis C in the 1970s and ’80s, has been called the worst treatment disaster in NHS history.

Many patients had a blood-clotting disorder and relied on regular injections of clotting agent Factor VIII,  made from human blood.

As Britain was running low on supplies, Factor VIII was imported from the US, where prison inmates and others were paid cash to give blood.

More than 25,000 people could have been affected, the inquiry heard in September.

The GIAA report released to Mr Evans said around 450 files had been checked out by Department of Health and Social Care (DHSC) staff.

A further 500 files were checked out from DHSC archives by “officers from the Department for Education in 2006 and have not been returned.”

DHSC would not disclose the files’ content, saying the majority have now been accounted for and it is working to locate the remainder.

Mr Evans said the report disproves ministers’ claims that all papers relating to the scandal have either been made public or destroyed.

“The undoubted question that arises now from victims and families is why were the files removed and was this part of a cover-up to prevent them knowing the full truth about what happened?” he asked.

Mr Evans’s solicitor Des Collins, whose firm is acting in more than 1,000 cases, said: “We know that there has been a government cover-up.

“We need to get to the bottom of why this happened, exactly what was in the files and what the people who in effect ‘made them disappear’ were trying to hide.”

Former health secretary David Owen said there had been a “cover-up,” with “incriminating evidence” suppressed by the government to avoid legal action.