UK retail giant Marks & Spencer tops a new "Customer Loyalty Index" by apparel fit preference specialist Fits.me.

The company conducted a survey of over 2,000 UK adults, asking them to identify up to three clothing brands or retailers to which they consider themselves most loyal. 

The top 10 brands to whom customers are the most loyal are:

Rank/Apparel retailer(brand)/Share of mentions
 

1. Marks & Spencer, 12.0%
2. Next, 9.6%
3. Primark, 5.9%
4. Debenhams, 5.1%
5. New Look, 4.7%
6. H&M, 3.9%
7. Asda (George), 3.7%
8. Tesco (F&F), 2.9%
9. Matalan, 2.7%
10. ASOS, 2.3%

Fits.me also created a list of the UK's most popular retailers for its survey, which was also topped by M&S, Next and Primark. A majority, 71%, of the people surveyed by Fits.me said they consider themselves loyal to either one, two or three clothing retailers or brands. Less than a fifth, 16%, said they weren't loyal to any clothing retailer or brand.

“While it’s clearly very difficult for apparel brands to secure the expressed loyalty of even just one in forty people, as the ASOS share of mentions received clearly illustrates, loyalty itself is very clearly not dead. With all retailers trying to achieve this on a daily basis, this response suggests retailers still have improvements to make,” said Stuart Simms, Fits.me’s chief executive officer.

The main factor that would improve a customer's loyalty to a retailer was if it "stocks clothes that fit my needs and preferences," chosen by 29% of respondents.