Double-digit growth in food-to-go helped Greencore (GNC) push up revenues 8.1% to £691.6m during the first half and raise its dividend.

The UK food-to-go business, made up of sandwiches, sushi and salads and represented more than 40% of group sales, grew at 13.1% in the six months to 25 March 2016 – and by 11.5% in the US.

The increases drove a 8.7% jump in sales at the convenience foods division to £667.9m, with chilled ready meals market also up 1.7% in the period.

Greencore raised its interim dividend 6.3% year on year to 2.6p per share on the back of the results.

CEO Patrick Coveney said: “Greencore has performed strongly in the first half of the year. Our strategy of focusing on the UK and US food-to-go markets is working well and we are continuing to invest in capacity and capability initiatives to support the substantial future growth pipeline. We are confident of further progress in the months and years ahead.”

Underlying operating profits climbed 8.5% to £43.5m, but exceptional charges of £6m related to US site closures and pre-commissioning costs at the new facilities in Northampton and Seattle, as well as one-off items linked to former sugar processing sites, pushed down pre-tax profits to £20.8m, compared to £26.3m a year ago.

Greencore has invested heavily in recent years constructing its new manufacturing facility in Northampton, which services Marks & Spencer.

The business said that good progress had been made on the construction of an additional unit at the site, which is due to be commissioned in spring 2017. Greencore added it had separately decided to add several new production lines at its other UK sandwich facilities to meet growing demand and future new business wins.

Net debt increased £50.5m in the half to £316m at the period end as a result of the high levels of capital investment in production capacity.

Despite the growth in revenues, shares fell 1.1% today to 382.1p as Greencore warned of the turbulent trading conditions as the big supermarkets continue to fight a price war.

“The UK backdrop is expected to remain uncertain given the changing nature of the grocery industry and other potential economic headwinds,” the business said in its outlook.