Retail sales of the Coca-Cola brand jumped 2.9 per cent year-on-year to £292.93m in the three months to 23 June, according to IRI data. The volume (number of litres) of the drink sold leapt 2.9 per cent to 272.17 million.

The increases contrast sharply with the same period last when value and volume sales fell 2.2 per cent and 5.8 per cent respectively.

The brand appears to have gained at the expense of its great rival, Pepsi. The rate of increase in sales growth for Pepsi was less than half that of Coca-Cola’s at 1.1 per cent. The volume of Pepsi sold fell 2.4 per cent to 102.8 million.

Again, the disappointing quarter contrasts with the same period in 2012, when Pepsi outperformed its rival growing value sales and volume by 5.5 per cent and 10 per cent respectively.

In the year to 23 June, sales of the Coca-Cola brand rose 2 per cent year-on-year to £1.22bn, according to IRI, while volumes rose 1 per cent. Sales of Pepsi were up 1.1 per cent but volume was down 0.1 per cent.

Pepsi’s sales growth outpaced Coca-Cola in both the on and off-trade in 2012, according to the Britvic Soft Drinks Report. 

Coke launched its Share a Coke campaign, which sees branding replaced with 150 of the country’s most popular names on bottles of Coca-Cola, Diet Coke and Coke Zero, in April. The campaign has lifted perception of the Coca-Cola brand in the UK, according to YouGov’s BrandIndex, as well as creating considerable buzz around the brand on social media.

The company will be buoyed by the IRI data as it had hoped the campaign would spur demand as it did in Australia and New Zealand, where it is said to have boosted sales by 4 per cent.

Coke will also be hoping the success will be replicated in the rest of Europe – the Share a Coke was rolled out across the continent following its UK launch. Sales volumes across Europe plummeted 4 per cent for the three months to 30 June, while revenue declined 1 per cent year-on-year to  $1.5bn (£999.6bm). 

The slump hit global volumes, which fell 1 per cent over the same period and sales fell 3 per cent year-on-year to 12.75bn (£8.6bn) from $13.08bn (£8.6bn).

Coke declined to comment on the data.