There were more than 2,000 across the country, each appointed by the council for the area it served, and containing a bevy of councillors.

At first, the local tribunals had only modest powers. They dealt with men who had already enlisted for military service under the ill-fated ‘Derby scheme’, which was either the beginning of conscription or a last, desperate attempt to avoid it. Introduced in late-1915 and named for Lord Derby, who had just been put in charge of military recruiting, the scheme promised men who enlisted that they wouldn’t have to serve until others had been called. But those men had, by the mere act of enlisting, made themselves soldiers. All a local tribunal could do was postpone the date of their call.

I discovered the case of Joseph Blackburn in the surviving records of the tribunal that sat in Thornton, near Blackpool. He was a Derby scheme man and his call-up was postponed twice. Ultimately, though, Joseph would go to war.

Voluntary enlistment didn’t produce recruits in the numbers the Army required. In the first half of 1916, therefore, the government brought in two Military Service Acts, which introduced conscription for the very first time. The local tribunals would now have to decide when men who were already soldiers should be called up, but also whether men who had hitherto been civilians could be required to serve at all. They would have the power to make a man exempt absolutely, temporarily or upon particular conditions.

There were several grounds for exemption, including ill-health or infirmity and the possibility of serious financial or domestic hardship if a man were required to serve. The statutes even introduced the idea of conscientious objection, although that never came up in the records I saw. Joseph was made exempt and his call-up postponed. The Thornton tribunal accepted that he was a market gardener and that it was ‘expedient in the national interest’ that he should follow that trade. His exemption wasn’t absolute, but its precise terms are irrelevant, because all too soon, it was taken away.

There was, in fact, an inconvenient truth of which the tribunals rarely spoke: although the government had promised to respect their decisions, and although it remained true to that promise throughout the war, they had little in the way of legal force and their decisions were not binding. It is hard to imagine a tribunal being permitted to operate on that basis today. Men who appeared before the tribunals often spoke for themselves, and while some chose to instruct a solicitor, only a very few also had counsel. The case for the Army, meanwhile, was put by a military representative, often a former soldier. In Joseph’s case, he was a former actor, who had once shared a stage with Lillie Langtry and was secretary of a local golf club.

Any appeal would lie to an appeal tribunal, and there was one of these for each county in the land. The Lancashire one had four separate sections, corresponding to the Quarter Sessions divisions, and when Joseph’s case was considered in Preston, his exemption was confirmed. The members of the Lancashire tribunal included industrialists, land-owners and the odd solicitor, barrister or judge, as well as a significant number of politicians. Usually, these were Conservative, Liberal or – given the times – Liberal Unionist politicians. The law required Labour to be represented as well, but the representatives in question were invariably ones who did not share the distaste for the war that was otherwise common on the Left. It is striking, in fact, how many of those who represented the labour movement on military service tribunals eventually came into conflict with the movement’s official political party.

It was the job of the appeal tribunal to re-hear the cases that came before it, and to decide each one afresh according to its findings. The tribunal would have all the powers available to the local councillors at the earlier stage. The same was true of the Central Tribunal, which sat in Westminster and was the ultimate authority in cases of this kind. The Central Tribunal didn’t close until September 1922 and held close to 600 sessions. At the height of its operations, it was sitting almost every day and sometimes dividing into two in order to get through its work.

At the time of Joseph’s case, the Central Tribunal was presided over by the fourth Marquess of Salisbury. The son of the last man to lead the country from the House of Lords, Lord Salisbury had fought in the Boer War, been a minister under his father and served in the Cabinet. A Conservative politician, he was a staunch defender of the Established Church, and he had been one of the most senior peers to oppose Lloyd George’s ‘People’s Budget’.

Among the tribunal’s other members were three lawyers. Sir Francis Gore was a barrister, related by marriage to Lord Salisbury. He had been a Recorder and then the Solicitor to the Board of Inland Revenue. Evan Charteris and George Talbot were also barristers, soon to be knighted. Charteris had practised at the parliamentary Bar and taken Silk before fighting in the war (even though over 50 years old) and was a celebrated biographer. Talbot, meanwhile, had been the Chancellor of several Anglican dioceses, would sit on a Royal Commission and had been the author of a number of learned works.

Lord Salisbury, Sir Francis and Mr Talbot made up half the tribunal that sat when Joseph’s case was considered, the other members being a Liberal MP, a retired colonial administrator and a wool magnate from West Yorkshire. In May 1917, the Central Tribunal decided that Joseph wasn’t a market gardener at all, but a mere ‘hawker’ of fruit and vegetables, and took away the exemption he had been given several months before. Within weeks, he was putting on a khaki tunic.

The decision in Westminster caused so much consternation in Thornton that the town’s tribunal went on strike. For several weeks in the summer of 1917, not a single military service appeal was heard there. By the time the councillors returned to their judicial work, a sizeable backlog of cases had built up. What caused most consternation was the suspicion that Lord Salisbury and his colleagues had seen evidence that wasn’t produced in Thornton or Preston. That would be contrary to modern-day expectations, of course, including those created by tribunal rules of procedure. It would also breach rules the Central Tribunal had set for itself.

In the early days of its existence, the tribunal had tried to decide how it should behave. It said, first, that it would never deign to explain its decisions – which might, again, cause difficulty today – and then it turned its attention to the question of disclosure.

The tribunal said that where it received fresh evidence that was relevant to an appeal, it would send that evidence to the man concerned. Having seen the Westminster records I think the Central Tribunal breached this undertaking in Joseph’s case. The records suggest, in fact, that the tribunal realised it had made a mistake, but that made no difference to Joseph.

In the dog-days of August 1918, he was killed in action as he scrambled across farm-land close to the River Somme. No Westminster man had thought to call him home.

Contributor Dr David Hewitt is a tribunal judge and a writer. Joseph, 1917 is published by Matador