Many Index stores were attached to Littlewoods stores. It was a well-known retailer in the 1980s and the 1990s, but after sales began to decline in the 2000s, its popularity became disputable and it started losing many customers to its rival, Argos.
During their 20-year history, Index lost £100 million, eventually causing Littlewoods to sell the stores. Many of the stores were purchased by Argos.
Similarities to Argos
Both Argos and Index issued catalogues containing very similar items, although Argos has more appeal to the UK market than Index had in the later years. They both had jewellery counters, stock checkers, the same basis of catalogue slips and the same type of organisation, with the customer having to state the catalogue number when ordering products from the tills.
Differences from Argos
Index had a number of slight differences when compared to Argos. Some Index stores were situated inside Littlewoods stores, either upstairs or below ground level. These were less accessible than Argos stores, which have ground-level shop floors. Also, Index stores were usually smaller than Argos stores, as there was a smaller product range. However, a large number of Index stores were not in Littlewoods stores and were able to carry more stock than Argos.
Index offered a free home delivery option for any item not available in stock on that day, instead of customers having to come back into the store. Since the closure of Index, its rival, Argos implemented a similar system, however, customers still have to return to the store to collect the items.
Littlewoods closed all the stores in 2005. Most of the stores were sold to Argos, Index employees at the Index stores were transferred to Argos. 
Argos also acquired the rights to Index.co.uk and the Index brand.