COMPENSATION to victims of major scandals including Windrush, infected blood and Post Office Horizon IT could reach an estimated £15 billion — with the vast majority still not paid, the public spending watchdog found today.

Less than a quarter of this sum had been paid out by February this year, the National Audit Office (NAO) said.

The watchdog said more recent schemes have learned from the shortcomings of others which were subject to delays and backlogs, but many victims still face lengthy waits for financial redress.

Public accounts committee chairman Sir Geoffrey Clifton-Brown said that the near-£15bn sum “lays bare the scale of suffering” to victims who have endured “terrible harms and injustices.”

The watchdog’s report said that while the government had handed out about £3.5bn in total across seven schemes, up to another £11.4bn is potentially yet to be paid.

This takes the potential total to an estimated £14.9bn.

Sir Geoffrey said: “Much of this has not yet been paid, despite many of the harms stretching back years and, in some cases, decades.

“Government has historically underestimated the complexity of these schemes, meaning that people are waiting too long to receive payments.”

The watchdog considered seven government schemes related to four major scandals and said most of the estimated total — about £12.8bn — is expected to go to victims of the infected blood scandal.

The NAO highlighted that some eligible people have been waiting more than a year after submitting their claim before receiving a payment.

It stressed that all schemes have more to do to reach as many potentially eligible people as possible and support them to make claims.

Gareth Davies, head of the NAO, said: “People who have experienced harm should be able to expect a clear process for claiming compensation and no unreasonable delay in processing their claim.”

The government said that as of the end of March “more than £5.1bn has been paid in compensation through these or similar interim schemes.”

It said: “We are constantly working with the relevant communities to improve the take-up and delivery of compensation and have delivered numerous improvements to our schemes in response to recommendations in recent years.

“The rate of compensation paid shows this government is serious about delivering justice as swiftly as possible.”