In Paris, he first came into contact with Jewish anarchism. In Spring 1893, he was invited to meeting of Jewish anarchists, which he attended and was impressed by. Though
neither a Jew by birth nor by belief, he ended up frequenting the group's meeting, eventually holding lectures himself. Solomon Rappaport, later known as S. Ansky, allowed Rocker to live with him, as they were both typographers and could share Rappaport's tools. During this period, Rocker also first
came into contact with the blending of anarchist and syndicalist ideas represented by the General Confederation of Labor (CGT),
which would influence him in the long term. In 1895, as a result of the anti-anarchist sentiment in France, Rocker traveled to London to visit the German consulate and examine the possibility of his returning to Germany but was told he would be imprisoned
Rocker decided to stay in London. He got a job as the librarian
of the Communist Workers' Educational Union, where he got to know Louise Michel and Errico Malatesta, two influential anarchists. Inspired to visit the quarter after reading about "Darkest London" in the works of John Henry Mackay, he was appalled by the poverty he witnessed in the predominantly Jewish East End. He joined the Jewish anarchist Arbeter Fraint group
he had obtained information about from his French comrades, quickly becoming a regular lecturer at its meetings. There, he met his lifelong companion Milly Witkop, a Ukrainian-born Jew who had fled to London in 1894. In May 1897, having lost his job and with little chance of re-employment,
Rocker was persuaded by a friend to move to New York. Witkop agreed to accompany him and they arrived on the 29th. They were, however, not admitted into the country, because they were not legally married. They refused to formalize their relationship. Rocker
explained that their "bond is one of free agreement between my wife and myself. It is a purely private matter that only concerns ourselves, and it needs no confirmation from the law." Witkop added: "Love is always free. When love ceases to be free it is prostitution."
The matter received front-page coverage in the national press. The Commissioner-General of Immigration, the former Knights of Labor PresidentTerence V. Powderly, advised the couple to get married to settle the matter, but they refused and were deported back to England on the same ship they had arrived
Unable to find employment upon return, Rocker decided to move to Liverpool. A former Whitechapel comrade of his persuaded him to become the editor of
a recently founded Yiddish weekly
newspaper called Dos Fraye Vort (The Free Word), even though he did not speak the language at the time. The newspaper only appeared for eight issues, but it led the Arbeter Fraint group to re-launch its eponymous newspaper and invite Rocker to return to the capital and take over as its editor.
Although it received some funds from Jews in New York, the journal's financial survival was precarious from the start. However, many volunteers
helped by selling the paper on street corners and in workshops. During this time, Rocker was especially concerned with combating the influence of Marxism and historical materialism in London's Jewish labor movement. In all, the Arbeter Fraint published twenty-five essays by Rocker on the topic, the first ever critical examination of Marxism in Yiddish, according to William J. Fishman.
Arbeter Fraint's unsound financial footing also meant Rocker rarely received the small salary promised
to him when he took over the journal and he depended financially on Witkop. Despite Rocker's sacrifices, however, the paper was forced to cease publication for lack of funds. In November 1899, the prominent American anarchist Emma Goldman visited London and Rocker met her for the first time. After hearing of the Arbeter
Fraint's situation she held three lectures to raise funds, but that was not enough.
Not wanting to be left without any means of propaganda, Rocker founded the Germinal in March 1900. Compared to Arbeter Fraint,
it was more theoretical, applying anarchist thought to the analysis of literature and philosophy. It represented a maturation of Rocker's thinking towards Kropotkin-ite anarchism
and would survive until March 1903. 1902 saw the London Jews being targeted by a wave ofanti-alien sentiment, while Rocker was away for a year in Leeds. Upon return in September, he was happy to see the Jewish anarchists had kept the Arbeter Fraint organization alive. A conference of all Jewish anarchists of the city on December
26 decided for a re-launch of the Arbeter Fraint newspaper
as the organ of all Jewish anarchists in Great Britain and Paris and made Rocker the editor. The first issue appeared on March 20, 1903. Following the Kishinev pogrom in
the Russian Empire, Rocker led a demonstration in solidarity with the victims, the largest ever gathering of Jews in London. Afterwards he traveled to Leeds, Glasgow,
andEdinburgh to lecture on the topic.
From 1904, the Jewish labor and anarchist movements in London reached their "golden years", according to William J.
Fishman. In 1905, publication of Germinal resumed, it reached a circulation of 2,500 a year later, while Arbeter
Fraint reached a demand of 5,000 copies. In 1906, the Arbeter Fraint group finally realized a long-time
goal, the establishment of a club for both Jewish and gentile workers. The Workers' Friend Club was founded in a former Methodist church on Jubilee Street. Rocker, by now a very eloquent speaker, became a regular speaker. As a result of the popularity of both the club and Germinal beyond the anarchist scene, Rocker befriended many prominent non-anarchist Jews in London, among them the Zionist philosopher Ber Borochov.
From June 8, 1906, Rocker was involved in a garment workers' strike. Wages and working conditions in the East End were much lower than in the rest of London and tailoring was the most important industry. Rocker
was asked by the union leading the strike to become part of the strike committee along with two other Arbeter Fraint members. He was a regular speaker
at the strikers' gatherings. The strike failed, because the strike funds ran out. By July 1, all workers were back in their workshops.
represented the federation at the International Anarchist Congress in Amsterdam in 1907. Errico Malatesta, Alexander Shapiro, and he became the secretaries of the new Anarchist International, but it only lasted until 1911. Also in 1907, his
son Ferminwas born. In 1909,
while visiting France, Rocker denounced the execution of the anarchist pedagogue Francisco Ferrer in Barcelona, leading him to be deported back to England.
In 1912, Rocker was once again an important figure in a strike by London's garment makers. In late April, 1,500 tailors from the West End, who were more highly skilled and better-paid
than those in the East End, started striking. By May, the total number was between 7,000 and 8,000. Since much of the West Enders' work was now being performed in the East End, the tailors' union there, under the influence of the Arbeter
Fraint group, decided to support the strike. Rudolf Rocker on the one hand saw this as a chance for the East End tailors to attack the sweatshop system, but on the other was afraid of an anti-Semitic backlash,
should the Jewish workers remain idle. He called for a general strike. His call was not followed, since over seventy percent of the East End tailors were engaged in the ready-made trade, which was not linked with the West End workers' strike. Nonetheless, 13,000 immigrant garment workers from
the East End went on strike following a May 8 assembly at which Rocker spoke. Not one worker voted against a strike. Rocker became a member of the strike committee and chairman of the finance sub-committee. He was responsible for collecting money and other
necessities for the striking workers. On the side he published the Arbeter Fraint newspaper on a daily basis to disseminate news about the strike. He spoke at the workers' assemblies and demonstrations.
On May 24 a mass meeting was held to discuss the question of whether to settle on a compromise proposed by the employers, which did not entail a closed union shop. A speech by Rocker convinced the workers to continue the strike. By the next morning, all of the workers' demands were met.