The 1930s were a defining period in Anglo-Jewish history. Externally, Britain's Jews were confronted, both at home and abroad, with the growing threat of political antisemitism, most conspicuously in its fascist guise.

Internally, meanwhile, the decade was characterised by discord within a community that, after quadrupling in size during half-a-century of mass immigration, had taken divergent socio-economic, political and religious paths, and was now experiencing an intense, often antagonistic, struggle over the balance of power within and between its various institutions.

Compounding these difficulties, it is often claimed, was the fact that the traditional Anglo-Jewish leadership - in particular the Board of Deputies - failed to fulfil its responsibilities to the community during this troubling time.

Such criticism has centred on three related charges. The first regards the alleged attitude of the Jewish elites, variously described as "complacent", "apathetic" and "naive". These "bourgeois" Jews, safely ensconced in their "gilded ghettos", were supposedly unable to understand the nature and severity of the domestic fascist threat, nor the fear and anger it engendered among the working-class Jews who bore its brunt.

Second, it was felt that this flawed perspective led the communal leadership to produce a defence policy that was "timid", "passive" and "lack-lustre". By refusing to confront the fascists directly, and instead focusing on "apologetic" endeavours – such as anti-defamation propaganda and improving the behaviour of Jews themselves - the Board's approach was not only ineffective but, by taking antisemitic slanders at face value and even suggesting that they may have some credence, was actually counter-productive.

The Board used its power to influence Ministers in the fight against fascism

Finally, it is suggested that, as a consequence of the foregoing, the Board was responsible for "tearing Anglo-Jewry apart". Because of its "extreme reluctance to combat antisemitism", as well as an "arrogant" and "condescending" attitude towards Jews lower down the social rungs who favoured a more active response to fascism, the Board further alienated the "new" Jewish community - largely working-class Jews of recent immigrant extraction - from the traditional, anglicised leadership.

This pushed the former to seek new forms of representation, such as the Jewish People's Council Against Fascism and Anti-Semitism, an East End defence body.

Yet on each of these three counts, new historical evidence - in particular from the Board's own defence archives, which until their recent transfer to the Wiener Library were relatively inaccessible to researchers - suggests that academic and popular perceptions of the role of the Anglo-Jewish leadership during this period should be revised.

In terms of its approach to domestic fascism, the Board was, indeed, initially rather cautious. This, however, reflected the fact that Britain's only fascist organisation of any prominence, Oswald Mosley's British Union of Fascists (BUF), made great effort during its first two years of existence to obfuscate its antisemitism and, at that stage, did not represent an explicit threat (indeed, it even appears to have had a handful of Jewish members in its early days). However, once the BUF had dispelled any ambiguity over its attitude towards Jews, and commenced its viciously antisemitic East End campaign in late 1935, the Board's attitude shifted accordingly.

It expressed sympathy for those Jews who were confronted with the fascists' verbal and physical intimidation. After attending a Blackshirt meeting in early 1936, the Board's president, Neville Laski, wrote privately of how "horrified, insulted and incited" he had been by the "vulgar, abusive, provocative tirades" made by the speaker, admitting that he had "needed all my self-restraint… to refrain from physical violence".

In a letter to the Jewish Chronicle in June, the Board's vice-president assured the community that "the leaders of Anglo-Jewry are fully alive to the poisonous seriousness of the attacks" being made by fascist "hooligans" and to the "justifiable anxiety" they had elicited among Jews. Such statements were not merely intended to mollify an increasingly restive East End Jewry, but were also translated over the following months into a comprehensive anti-fascist campaign - albeit one that was, by necessity, conducted partly in secrecy.

A central feature of these efforts was intensive lobbying of the authorities. Laski recognised that the state was Britain's most potent anti-fascist force, and he used the Board's privileged position to ensure that constant pressure was applied to the authorities to enforce measures to restrict fascist activity and protect Jews from it.

In 1936, for example, Laski and his two vice-presidents met John Simon, the Home Secretary, whom they upbraided for "the apparent immunity and licence enjoyed by the Fascists" in east London and urged to take a tougher stance. The efficacy of their exhortations was immediately evident, with Simon circulating orders just a few days later for police to take "intensive action… to suppress" fascist "Jew baiting", particularly in areas of high Jewish population.

Over the rest of the decade, senior figures at the Board maintained regular contact with decision-makers, relaying concerns of the Jewish community and seizing upon any indication that fascists were being treated with undue leniency - or Jewish anti-fascists with undue severity - by the authorities. In 1940, the Board played a role in the ultimate demise of the BUF and other antisemitic organisations, by identifying leading members for internment.

The Board also attempted to thwart the fascists' political ambitions. It kept meticulous track of prospective fascist electoral candidates, and discreetly offered its support to anyone standing against them. When a number of Blackshirts stood in local elections in east London in 1937, the Board produced and distributed anti-fascist campaign material and, on election day, arranged for 160 cars to ferry Jewish voters to the polls.

Publications - with titles such as Do you know these facts about Mosley and his Fascists? – attacked the BUF directly, while an outdoor meeting campaign was organised that deliberately shadowed fascist events, aiming to immediately refute any antisemitic charges. As such, these events were often held in extremely hostile territory, with the Board's speakers regularly facing verbal hostility and even physical violence, necessitating the employment of stewards provided by the Association of Jewish Ex-Servicemen (AJEX). During the second half of the 1930s, the Board held more than 3,000 public meetings and distributed over two million copies of 50 or more publications.

Perhaps the most interesting - and least well known - facet of the Board's work was its successful infiltration of a number of antisemitic organisations. Working in absolute secrecy, Laski established a network of informants and moles, beginning in 1936 when he recruited, "by devious means", an officer within the BUF's headquarters. "Captain X", as he was referred to, passed on details of upcoming Blackshirt meetings, allowing the Board to plan countermeasures against them, as well as the names of BUF members, which were forwarded to the police.

Inspired by this success, Laski secured the services of a former Special Branch inspector, Cecil Pavey, who, under an assumed identity, was tasked with penetrating other groups on Britain's radical-right fringe. Most significantly, he integrated himself into the Nordic League, a secretive pro-Nazi, anti-Jewish body headed by the Conservative MP Archibald Ramsey.

Pavey's detailed reports provided evidence not only of the Nordic League's extreme antisemitism (which extended to the effective endorsement of genocide), but also of its links to the Nazi regime (which had become particularly apparent after he attended a Nordic League "summer school" in Germany). Pavey and other agents working for Laski were also able to gain access to a number of other organisations, including the Imperial Fascist League, the British People's Party and The Link.

The information procured from these sources provided the Board great leverage in its dealings with the authorities, whose own ability to monitor and investigate such groups was limited by budgetary constraints. During one meeting at the Home Office in 1939, Laski stressed that the evidence he was conveying clearly indicated that the Nordic League was not just a threat to the Jewish community, but to the government, to public order and, given the growing prospect of war with Nazi Germany, to "broader national and international questions".

The officials he had met subsequently admitted in private discussion that the reports did "contain some astonishing material", in particular regarding the League's links to the Nazis. The Board later claimed that it had been thanks to its findings that the authorities first became aware of Ramsey's involvement in this potentially treasonous activity. He was subsequently interned during the war, while at least one Nazi agent operating in Britain was arrested on the strength of the BUF's evidence.

While the Anglo-Jewish leadership did, then, undertake far more vigorous anti-fascist activity than its contemporary critics, and many subsequent researchers, have given it credit for, it is fair to say that the Board never fully endorsed the type of confrontational activity favoured by many Jews, who believed that the only effective way to silence the fascists was to disrupt their meetings, block their marches and, where necessary, meet the threat of violence in kind.

Senior figures at the Board understood feelings that motivated such sentiment. The secretary of its defence committee told the Evening Standard that Jews should not be blamed for occasionally responding aggressively to the fascists, given that "it is not human nature… to stand calmly by while Blackshirts shout insults".

Laski warned the Home Office that "any self-respecting Jew" in the crowd at antisemitic meetings would understandably "have the greatest difficulty in restraining himself, not only vocally, but even physically".

However, the Board attempted to discourage Jews from direct physical confrontation with the fascists. This was, in part, an inevitable product of the Board's position: disruptive activity was often illegal, making it difficult for the community's official representative body to give its blessing. But it also reflected an understanding that Jewish aggression - however justified - played into the hands of the fascists, who had cultivated an image of victimhood at Jewish hands that they used to justify their "defensive" violence and antisemitism.

This was something even the most combative of Jewish anti-fascists came to realise. In 1936, the Jewish People's Council had taken the lead in organising the protests that led to the famous Battle of Cable Street; yet within a year it had mounted a complete about-turn, with its leaflets now warning that the BUF's "purpose is… to cause disorder and incite breaches of the peace", and that Jews should 'not fall into their trap' by disrupting Blackshirt events.

The converging positions of the Board and the JPC, who are usually portrayed as intractable antagonists, is illustrative of the fact that, in fact, the shared threat of fascism actually drew Britain's Jews closed together. The two organisations had begun exploring the possibility of collaboration as early as 1936, soon after the JPC's formation.

While their initially contrasting approaches precluded any deal, the Board's increasingly explicit opposition to fascism, and the JPC's move away from disruptive forms of activity, opened the way to renewed negotiations in 1938. Later that year, the two organisations began to work alongside one another. The following year, the JPC agreed to disband, and absorb itself entirely into the Board's defence apparatus (though this arrangement was prevented by the outbreak of war).

Given that even the most vocal of Jewish anti-fascists had now come to accept the Board's leadership in this area, it is no surprise to learn that, in the meantime, most of the rest of Anglo-Jewry had also come out in support of Laski's defence campaign. Over 1936-39, his policies received the endorsement of friendly societies (notably the Association of Jewish Friendly Societies, which represented some 50,000 Jews); ex-servicemen's associations (such as AJEX, whose offices hosted the Board's East End defence council); the JC (which provided positive coverage of the Board's work and encouraged donations to its defence fund); the leaders of provincial Jewish communities; synagogues; Jewish trade and business bodies (who proved the most generous donors to defence work); the Zionist Federation; and even significant sections of working-class Jewry in places such as east London.

It was not just institutions that threw their lot in with the Board: thousands of individuals made donations to its defence fund, which, in the space of just five months after a fundraising drive began in October 1938, raised £53,000 – enough to cover over three years of defence work.

The evidence outlined above challenges fundamentally our collective memory of this pivotal era. Faced by the most serious challenge in their modern history, Britain's Jews did not, as is often believed, cleave irrevocably apart; rather, they overcame initial differences to present a united front against a common enemy.

Moreover, they did so by rallying behind a communal leadership which proved itself not just willing but also capable of responding to this threat in a measured, comprehensive and effective manner.

Given the continued existence - and, indeed, recent rise – of the exclusionary radical right in Europe, the example of a small minority uniting to successfully counteract such a threat, in collaboration with external allies, should not be of purely historical - or Jewish - interest.

Daniel Tilles's new book, 'British Fascist Antisemitism and Jewish Responses, 1932-40', extracts of which appear above, is published by Bloomsbury.