AO.com has posted widening losses at the interim mark despite healthy sales rises across the UK and Europe.

The electricals etailer recorded a group operating loss of £12m, compared with £2.8m the previous year, in the six months to September 30, which it attributed to its UK marketing and European expansion investments.

UK adjusted EBITDA fell 43% to £7.4m, and European adjusted EBITDA losses widened to €15.6m (£13.7m) from €14.3m (£11.6m) the previous year, which was compounded by currency fluctuations.

The online retailer’s UK revenue increased 7.4% to £316.8m while website sales jumped 9.9% to £282.5m, against AO.com said “a backdrop of a weaker macro-economic environment and strong comparables”.

The retailer’s European revenue soared 60.5% to €58.1m (£51.2m) despite minimal marketing activity.

AO.com launched a transactional mobile app across all of its territories during the period and expanded its product range in the UK to include mobile phones and smart home devices.

Chief executive Steve Caunce said: “We are broadly on track with our plans for the year as a whole – with the positive impact of improving sales growth through the first half of the year combined with the first half biased phasing of our marketing spend – in spite of the challenging UK market conditions.

“Our European operations continue to perform in line with the plan we’ve previously set out notwithstanding the adverse impact of foreign exchange rates on our reported performance.

“While we are mindful of macro-economic factors we remain confident that we are on track with our plans to be the best electrical retailer in Europe.”

The etailer said its full-year adjusted EBITDA was likely to come in towards the lower end of its predicted range.