IT IS said to be the most widespread miscarriage of justice in British legal history — and the scandal just gets bigger and bigger. It is nearly four years since the High Court ruled that the Post Office had falsely accused thousands of sub-postmasters of theft. And now the head of an inquiry into the scandal has revealed that “full and fair compensation” is being blocked.

Some of the Post Office’s victims were imprisoned. Others were forced into bankruptcy. Marriages were destroyed. Reputations were ruined. Some 59 have died while awaiting justice. Four took their own lives. Justice delayed for them proved, indeed, to be justice denied.

The sub-post-office scandal has been a catalogue of official arrogance, incompetence, and callous complacency, which sadly epitomises the Kafkaesque ordeal so often experienced by ordinary people at the hands of an uncaring corporate behemoth.

So far, we have learned that the Post Office knew early on that there were serious problems with the Horizon computer accounting system, which it had bought from Fujitsu to install in the nation’s sub-post offices. It covered up those problems in a clear perversion of the course of justice.

Next, it had to own up to the inquiry that it had failed to produce 1500 documents that it should have disclosed to its victims’ lawyers. Without evident irony, it blamed its own computer incompetence.

Then it was revealed that it had required investigators to categorise sub-postmasters according to an offensive racial classification — labelling black sub-postmasters as “negroid types” and those looking “Siamese” or “Philippino” as “Chinese/Japanese types”.

More recently, it was disclosed that Post Office bosses had been paid bonuses simply for co-operating with the inquiry; Nick Read, the Post Office chief executive, was embarrassed into handing back a paltry £13,600 of his £455,000 bonus — from his total pay packet of £870,000.

Most recently, Mr Read has expressed puzzlement that postmasters are not coming forward to the Criminal Cases Review Commission, which has the power to refer miscarriages of justice to the Court of Appeal. It is not hard to imagine why. Many, particularly the more elderly victims, must be feeling ground down by two whole decades of banging their heads against this recalcitrant, unlistening monolith — and dealing with the three separate, tardy, and inadequate compensation schemes that have been set up for the Post Office’s victims.

Three things should happen now. The Post Office should drop its opposition to the quashing of all the 2000-15 prosecutions, except where there is clear evidence of guilt separate from the dodgy Horizon computer records.

The Business Minister Kevin Hollinrake should bang heads together to ensure that all the victims are given compensation adequate to restore them to their previous standards of living. And the Government should pressurise Fujitsu to make reparation for the catastrophic failure of its computer system: to date, it has not paid one penny in compensation — and, indeed, has been given £3.5 billion in government business since 2013.

Earlier this month, Sir Wyn Williams, who is chairing the inquiry, announced that Post Office officials now face imprisonment — for as long as 51 weeks — if they fail to hand over any more documents to the public inquiry. He should now make clear that this is not an idle threat.