|Half year to 30 June|
|Headline operating profit||70.1||61.7|
|Amortisation of acquired intangible fixed assets||(1.9)||(2.3)|
|Net finance charge||(1.0)||(1.2)|
|Profit before taxation||67.2||58.2|
|Profit for the period||50.8||43.6|
Group revenue was £368.0m, an increase of 6.4% at actual exchange rates and 8.7% at constant currency. Headline operating profit for the six months increased by 14% to £70.1m (H1 2017: £61.7m), and return on sales increased to 19.0% (H1 2017: 17.8%). Headline operating profit at constant currency increased by 15% to £71.2m. Once again, increases in input costs were more than recovered via price increases and the Group maintained a strong focus on cost control and operational efficiency. Statutory operating profit grew to £68.2m (H1 2017: £59.4m).