Retail sales increased 6.5% in September year-on-year despite average store prices falling by 3.6%, according to data from the Office for National Statistics (ONS).

Growth was driven by online as ecommerce sales jumped 15.2% year-on-year and increased by 4.5% compared with the previous month.

However, sales were flattered by the period running from August 30 to October 3, which means they included the bank holiday weekend.  Figures from last September did not include the bank holiday weekend.

Deloitte head of consumer business research Ben Perkins said: “With the addition of the late August bank holiday weekend, it is no wonder that September has seen bumper retail sales numbers.”

Retail sales have now grown for the 29th consecutive month following the September increase.

Barclays head of retail and wholesale Ian Gilmartin said: “September’s ONS retail statistics show that it was a really impressive month for retailers, accelerating August’s strong numbers.

“Hosting the Rugby World Cup provided a timely boost to sales and helped the industry set a solid platform for the all-important Christmas period.

“Retailers are now readying themselves for Black Friday and finalising their preparations for Christmas, and it’s clear from my conversations with clients that there is a growing optimism in the industry, with retailers increasingly hopeful that higher levels of disposable income resulting from recent drops in food and fuel prices will lead to a positive outcome in the season ahead.”

Dan Wagner, founder and chief executive of Powa Technologies, added: “We can expect sales to ramp up ahead of Black Friday, Cyber Monday and of course, Christmas.

“However, retail sales figures have fluctuated this past year, so retailers must take steps to avoid being lulled into complacency.”