LONDON, United Kingdom — British suit retailer Moss Bros Group warned on Friday of a challenging year ahead, even as its online sales rose nearly 30 percent for the 23-week period to January 5.

The company, like other retailers, has faced lower traffic at its stores in the backdrop of sluggish British consumer spending and sentiment dampened by Brexit fears.

Moss, which wrapped up a busy week of Christmas trading updates from British retailers, said its e-commerce sales for the 23-week period rose 27.8 percent.

"We are encouraged that Moss has demonstrated its long awaited online credentials, one of the biggest investor concerns," Peel Hunt analysts said in a note.

However, a warning last month from online fashion group ASOS fuelled a Christmas crisis among Britain's retailers and showed that online-only clothing retailers were not immune to a deterioration in consumer sentiment.

Moss Bros' trading gross margins fell about 2.6 percent and like-for-like sales fell 1 percent as the company was forced to give steeper discounts than planned in the period post Black Friday.

Peel Hunt analysts, however, said the hit to gross margins was less than feared.

By Pushkala Aripaka; editor: Shounak Dasgupta.