It was a power which the British Government had nonetheless taken to itself under the Defence Regulations, and between 1939 and 1945 it was used to imprison some 2,000 people. Brian Simpson's verdict is that this was 'as gross an invasion of British civil liberty as could be conceived, only justifiable, if at all, by the grim necessity of the time.'
Professor Simpson's researches have been strenuous, but not always as successful as he would have liked. Much of what was done under Regulation 18B was not made public at the time; many of those arrested under it had been Fascists and excited little public sympathy; most of the relevant government records have been destroyed; access to much of what remains has been denied him. Given these constraints, he has succeeded in rending the veil of secrecy in a commendably large number of places.
He traces the evolution of the legislation and the administrative machinery involved: the Coercion Acts in Ireland in the last century and the Defence of the Realm Act of 1915, the Special Branch and MI5. The latter came into being on the recommendation of a Subcommittee on Espionage set up by Haldane in 1909. Simpson judges its report to be one of the more entertaining in the Public Records, 'rivalling in absurdity the file containing the Home Office Rules for the keeping of pet mice in convict prisons'.
Those who suffer detention generally find themselves in prison not for what they have done but for what the authorities suspect they might do if they remained at liberty. Most of the internments during the Second World War took place in the summer of 1940, when there was wide belief in the existence of a Fifth Column, and the Government decided to move against Sir Oswald Mosley and his British Union.
Simpson argues that the application of common sense to what is known about 18B suggests that many of those detained were in no sense significantly dangerous. They were certainly a bizarre galere. Mrs Beaumont of Freckenham was a masseuse working for Elizabeth Arden; Giovanni Celeste Sperni was a former Mayor of St Pancras. Prince Henry of Pless was the owner of vast estates in Poland; the Rev K P Scwabcher was Curate of St Mark's, Plumstead. Sir Barry Domvile was a retired admiral who was convinced that there was a baneful Judaeo-Masonic conspiracy at work in world history; Joe Beckett was the former British heavyweight boxing champion.
There is an absorbing chapter on the experience of detention. There was no provision for informing relatives that a detention order had been made, nor where the detainee was being taken. 'An arrest,' writes Simpson, 'was thus rather like a heart attack, or indeed a visit from the Gestapo, in its immediate social consequences.' The reactions of those detained varied hugely. Captain Thomas G St Barbe Baker MC came to identify Hitler with Christ and conducted bizarre religious ceremonies. At Ascot the Fascist inmates were initially demoralised and quarrelsome, but one of their number formed the 'Hail Mosley and Fuck 'Em All Association', and the letters HMAFEA began to be chalked on the camp walls.
Simpson traces the strain that detention placed on the wartime bureaucracy, the complications that arose once a number of detainees had recourse to the courts, and the gradual liberalisation of policy; the Mosleys were released in November 1943 and by the end of the following year only 65 detainees remained.
Was it all necessary? Simpson does not disguise his own unease at the violation of civil liberties, but in a concluding chapter presents the arguments on both sides with exemplary fairness. He acknowledges that the story of 18B provides a classic illustration of a problem with which liberal democracies find themselves confronted in times of crisis - how essential is it to their survival that they should in some ways cease to operate as liberal democracies until the threat recedes? 'Not all problems have solutions,' Simpson writes, 'and this is surely true of this particular problem.' He has illuminated it brilliantly. This is the sort of book that could give academic lawyers - and academic publishers - a good name.