The stories of the "rotten shirker" butcher of Finchley, of the German baker whose shop was destroyed by crowds shouting anti-German abuse, and of the last son at home whose four brothers had already died in the first world war are revealed in records released online by the National Archives at Kew.

Many of the files, which come from a tribunal that judged thousands of appeals against conscription, have supporting letters, typed or handwritten on shoddy wartime paper. Often the letters have heartbreaking pleas from relatives fearing they will be left destitute, or explanations from employers of how their businesses might be destroyed.

Some of the letters are more startling, however. There is the anonymous denunciation of the Finchley butcher Charles Rubens Bushey, which says: "He made a heap of money in this shop, he is a proper rotter of a man."

The case of Harry Ward, a 20-year-old conscientious objector who strikingly described himself as "foreign correspondent and bookkeeping clerk", led to questions in parliament over claims that the tribunal chairman told him that as a socialist it was impossible he was a man of conscience. Ward lost the appeal but survived the war.

The records of the 11,307 cases heard by the Middlesex military service appeal tribunal cover the period between 1916, when conscription was introduced, and the end of the war in 1918, and are rare survivors.

Once conscription was introduced, first for single and then for married men because volunteer numbers collapsed when it became clear the war would certainly not be over by Christmas, tribunals sat across the country, with local ones hearing initial claims and appeals sent to county tribunals.

At the end of the war the government ordered that all the tribunal records be destroyed on the grounds that they were too sensitive, with only the complete Middlesex records and another set from Scotland preserved as representative samples.

"Although the existence of these records was known, they have been very difficult to access and search, and extremely confusingly indexed," said Chris Barnes, a records specialist. "They now represent a treasury of hugely valuable material fascinating to social or family historians, searchable by name, place, or reason for appeal."

As some of the letters demonstrate vividly, much of the material is indeed sensitive, revealing bitter social divisions, families and neighbours feuding, and medical evidence thrown out.

One man had his doctor's testimony, affirming he had a deformed ankle, thrown out, only to be dismissed as unfit from the army two years later, over the same ankle.

Ruses struck up to avoid conscription, and what would have looked by 1916 like certain death, are evident.

Another butcher claimed his business was the only remaining shop in his area; so it was, but, as the tribunal discovered, only because he had bought out the competition to try to improve his appeal.

Even the specialists at the archives occasionally came across something that really startled them.

Harry Harris at his shop in a picture sent with his appeal against conscription. Photograph: Steve Parsons/PA

The wife of one Percival Brown, of West Green, wrote to the tribunal, but it was far from the usual heart-rending plea to allow his appeal.

She said: "I hope that you will not grant it, as he leads me such a life, I was looking forward to him joining up as I have had nearly 11 years of unhappiness through him. He never keeps his places long together, which as [sic] caused me to go short of money, food, besides selling part of my home."

The bitterness of the letter about the Finchley butcher, signed "your obedient servant, a father and householder", is striking. A friend heard the butcher boast five shillings that he would be let off again by the tribunal, for the sixth time.

The cause of the bitterness becomes clear at the end of the first page. "I am 68 years old and have had sons killed, one at the Battle of Mons, one six weeks ago, and a son in the North Sea." Whether the letter swung the tribunal or not, the butcher lost his appeal.

The German baker, Frederick Lunkenheimer, explained that his family had moved to Britain because his father hated war and that he too was a conscientious objector. Their bakery had already been vandalised and his family "grossly abused" in an outbreak of anti-German feeling at the start of the war.

The tribunal noted that Lunkenheimer was a confectioner as well as breadmaker, so his work could not be considered essential. He lost his appeal, but was assigned to war work in Britain rather than being sent to the front.

The tribunal in the end heard only 577 conscientious objection cases, just over 5%, and rejected most of them.

One railway clerk wrote a passionately argued two-page letter saying he would even work as a farm labourer if that were judged more useful than his present employment.

The fate of some of the objectors can be traced through the records of forces in the archives. If applicants refused to do war work under military orders many were sentenced to death, though that was often commuted to 10 years' imprisonment.

Part of John Gordon Shallis's appeal submission, describing the death of three older brothers. Photograph: Steve Parsons/PA

The most touching supporting evidence must be the photograph sent by Harry Harris of his immaculate grocery and hardware shop in Wood Green, with himself standing in the doorway in a spotless white apron.

He had already lost his two shop assistants to the war, he explained. "I shall have to close down. I lose my life savings as this is a one-man business. I have no one to leave in charge." He lost the appeal but was given a month to find somebody to run the shop; its fate is unknown.

The archivists found the case of John Gordon Shallis, a 19-year-old carpenter, particularly moving. His mother had broken her leg in a fall soon after learning that her first and second sons had died in the war; she was in hospital when she learned that the third son was dead too. By the time the tribunal sat a fourth had died. Shallis's appeal was allowed.

One man, Alfred Baggs, one of four sons of a pig farmer, first appealed and then agreed to serve if, he said, it would save his youngest brother. He wrote a furious letter in May 1918 on learning that the youngest had just been called up. "I am as positive as anyone could be that the lad would serve his country better at home than being in the army."

In September, with his farm business destroyed, and his youngest son still under threat of conscription, the father took his own life. If he had lived two months longer he would have seen the three elder sons come safely back from the war.

Of more than 11,000 cases heard by the tribunal most were rejected outright, and just 26 men succeeded in obtaining complete exemption from being called up.

Perhaps the most fortunate were the 1,001 men saved by bureaucracy: their cases were still waiting to be heard when the war ended.