IRN-BRU owner AG Barr’s shares fell almost 30 per cent on news the firm is expecting worse than expected first half results brought on partly by bad weather.

The City shuddered as the Cumbernauld-based firm said sales could be down by 10 per cent and profits by as much as a fifth compared to the same six months last year.

The firm said a combination of poorer weather and lack of a favourable backdrop facilitated in part by its preparations for the sugar-tax levy last year have this year hit expectations.

Sales for the 26 weeks to July 27 are now expected to be around £123 million.

The company reduced sugar content in Irn-Bru in a move that beat the levy but which has been suggested may have had an impact on how some customers view the famous brand.

READ MORE: Irn-Bru warns profits to plunge as sugar tax hits sales

Roger White, AG Barr chief executive, said Irn-Bru is performing robustly and the firm expects a strong second half.

He said: “We have to look backwards to get the context and last year was an unprecedented year for soft drinks because of a number of factors; the Soft Drinks Industry Levy implementation, and competitor pricing and promotional dynamics, weather, which was exceptional last year, and the CO2 crisis.”

Mr White added: “All of those things added together probably gave us a more significant competitive advantage in the market than even we appreciated.

“The last year’s comparative trading when you take account this year, particularly in Scotland and the north of England the weather has been markedly poorer than the prior year, and when you take account of those other factors like competitor pricing, promotional dynamics and CO2, we have had a tougher comparative year than we were anticipating and as a consequence we have seen a challenging particularly latter half to this first half, and that’s why we’ve put the guidance update out.”

READ MORE: Irn-Bru will pay sugar tax on new energy drink

Mr White said: “From a practical point of view the Irn-Bru brand continues to perform robustly, our innovation in things like Irn-Bru XTRA and the new Irn-Bru Energy drink are performing above expectations, our Rubicon business, in particular the carbonates and spring business is going well, so it is not a fundamental change to the business it is just purely the circumstantial position year on year.”

He added: “The impact of the legislative change was much more last year and that probably saw us getting a bit more of an advantage because we didn’t participate in any way materially in having to pass any levy costs on and change our promotional dynamics and things like the C02 shortage, where we managed to not have any material damage done, whereas others may have had probably more material damage done than we recognised and that gave us an unintended and unexpected and unquantified lift in our sales last year."

READ MORE: Irn-Bru shakes off sugar tax as profits rise

He said: “If it was just that it was a poor weather summer we would have sailed through, but when you add it all together it is just giving us a bit more of a headache than we were expecting and we have come out really to make sure we have guided the market.

“We have a strong second half planned with lots of activity in it and we will be out to try and beat rather than meet the guidance that we’ve given.”

Nicholas Hyett, equity analyst at Hargreaves Lansdown, said: “To say this is a curve ball is an understatement. Consumer goods companies like AG Barr are supposed to be reliable compounders, with sales that turn up come rain or shine.

"The cocktail of woes that have struck the group are more than a small disappointment, but it’s important not to lose sight of some of AG Barr’s underlying attractions.”

Russ Mould, investment director at AJ Bell, said: “One can excuse the drinks company for not selling as many products in these conditions; however, specific brand challenges with Rockstar and Rubicon are slightly concerning.”

Shares were down 28.31%, or 246p, at 623p at one stage on the news.