It was a newspaper of a new type, such as had never before existed in the history of the labour movement.

参考译文：它是如此新型的一种报纸，在劳工运动历史上从未出现过。

解答如下：

这里的 such 充当a newspaper of a new type的同位语成分，as 为关系代词引导定语从句。修饰先行词such. 关系代词 as在定语从句作主语。

主语：It

系动词：is

表语：a newspaper ofa new type

同位语：such

引导定语从句关系代词：as

定语从句:as had never existed in the history of the labour movement