(Sharecast News) - AG Barr reported a 5% increase in first-half revenue as the maker of Irn-Bru and other soft drinks shook off extreme wintry conditions to benefit from a hot early summer. The Glasgow-based company said revenue in the six months to the end of June rose to about £136m from £129.8m a year earlier. It left its annual profit guidance unchanged.Sales in the wider soft drinks market rose 4.5% in the first half as volumes rose 1.4%, supported by the start of the summer heatwave after sales were affected by freezing weather in the first quarter."Against this market backdrop our core brands have performed well," AG Barr said. "The Irn-Bru brand in particular has continued its positive growth momentum, with regular Irn-Bru increasing its volume and value share of the total soft drinks market alongside strong growth in Irn-Bru Xtra."AG Barr introduced a new lower-sugar recipe for Irn-Bru, its top selling brand, before the introduction of the soft drinks levy, also known as the sugar tax, in April. It also introduced Irn-Bru Xtra a sugarless version of the product, which is Scotland's best-selling soft drink and ranks third in the UK behind Coca-Cola and Pepsi.The company said it was waiting to see the full effect of the sugar tax and that the external landscape was volatile. Spending on brands, innovation and employees will squeeze margins moderately this year, it added.Roger White, AG Barr's chief executive, said: "We have delivered strong top-line growth in a period of considerable marketplace volatility and change. Our growth across core brands is especially encouraging and our strong second half brand and sales development plans give us confidence that we can deliver against our profit expectations."