IRN-BRU'S maker has warned its profits look set to collapse this year as customers turn away from its reduced-sugar drinks.

AG Barr also cited poor weather - particularly in Scotland - as being one of the reasons.

Bosses warned sales will drop 10 per cent and profits will be down by up to 20 per cent as they struggle against what was a strong year last year.

The company said the problem "has been exacerbated by some specific brand challenges, particularly in Rockstar energy and Rubicon juice drinks, as well as disappointing spring and early summer weather, most notably in Scotland and the North of England, and compounded further as we approach the half-year when the prior year comparative weather was at its peak".

AG Barr's Rubicon division has faced challenges since the introduction of the sugar-tax levy, with several drinks companies having to change their recipes to reduce sugar levels.

This has led to a backlash among some customers, who have complained about the new tastes.

The Rockstar energy division has also had to contend with a crackdown and awareness-raising by campaigners about teenagers drinking high-caffeine drinks.

Several supermarkets have banned sales of the products to under-18s.

AG Barr chief executive Roger White said that although the cocktail mixer division Funkin is growing well, it has been a challenging start to the year for the rest of the company.

He added: "Weather comparatives and trading, particularly in the impulse on-the-go market, have been even tougher than expected which, along with some brand-specific challenges, have led to a short-term impact on our financial performance.

"We are focused on returning to growth and will continue to take the actions we believe necessary to succeed in the dynamic environment within which we operate."

These actions include launching three new Rockstar drinks by the end of the summer and "recipe improvement activity" for Rubicon juice drinks.

Although, the company warned "the benefit of these actions will not be felt until later in the second half of the financial year".

Sales for the 26 weeks to July 27 are now expected to be around £123 million - down 10 per cent on last year - and further one-off costs can be expected to be announced later in the year, the company added.