Carphone Warehouse has reported strong sales growth outside its traditional category of mobile phones, but earnings at its core retail business were flat in a tough market.

Carphone reported that “non-cellular” revenues from products such as tablets and accessories climbed by more than 15% in the latter half of its last financial year.

Although such sales helped offset a lower contribution from pre-pay, they still only represent “a very small part of overall revenue” the retailer said.

The core retail business, Carphone Warehouse Europe, posted flat EBITDA of £219.6m last year on sales down 5.5% to £3.31bn. Like-for-likes fell 4.6%.

The retail division was affected by the shift to longer phone contracts in the UK and other “structural changes in certain European markets”.

Carphone continues to convert stores to its ‘wireless world’ model, which carries a wider product range. There are now 392 wireless world stores in the eight countries where Carphone operates. The retailer said: “We continue to see the benefits of this store format both in our financial results and in our customer service scores.”

At group level Carphone made a statutory pre-tax profit of £762.2m, compared to £67.2m the previous year. The leap reflected the sale of its share in US business Best Buy Mobile. Group headline pre-tax profit edged up to £58.3m from £56.3m.

Carphone chief executive Roger Taylor said: “We expect the consumer environment in Europe to remain difficult, but we see opportunities as well as challenges and are confident in our strategic positioning and operational execution.”