Judaism
Around the 1st century CE, there were several small Jewish sects: the Pharisees, Sadducees, Zealots, Essenes, and Christians. After the destruction of the Second Temple in 70 CE, these sects vanished. Christianity survived, but by breaking with Judaism and becoming a separate religion; the Pharisees survived but in the form of Rabbinic Judaism (today, known simply as "Judaism"). The Sadducees rejected the divine inspiration of the Prophets and the Writings, relying only on the Torah as divinely inspired. Consequently, a number of other core tenets of the Pharisees' belief system (which became the basis for modern Judaism), were also dismissed by the Sadducees. (The Samaritans practiced a similar religion, which is traditionally considered separate from Judaism.)
Reform Judaism
The next in size, by a wide margin, are the two British WUPJ-affiliates. In 2010, the Movement for Reform Judaism and Liberal Judaism respectively had 16,125 and 7,197 member households in 45 and 39 communities, or 19.4% and 8.7% of British Jews registered at a synagogue. Other member organizations are based in forty countries around the world. They include the Union progressiver Juden in Deutschland, which had some 4,500 members in 2010 and incorporates 25 congregations, one in Austria; the Nederlands Verbond voor Progressief Jodendom, with 3,500 affiliates in 10 communities; the 13 Liberal synagogues in France; the Israel Movement for Reform and Progressive Judaism (5,000 members in 2000, 35 communities); the Movement for Progressive Judaism (Движение прогрессивного Иудаизма) in the CIS and Baltic States, with 61 affiliates in Russia, Ukraine and Belarus and several thousands of regular constituents; and many other, smaller ones.