August retail sales volume growth was “exceptionally high” against last year, up 2.1%, as consumers continued to spend online.

Retail values increased 3.6% to £26.9bn against last year, according to the Office for National Statistics (ONS).

The ONS said sales growth was driven by the non-store retail sector, which predominantly comprises etailers, as well as retailers selling through mail order and market stalls.

The sharp growth was also result of low comparatives last year suffered due to consumers’ shunning shopping for watching the Olympic Games.

In August, retail sales volumes in the non-store sector surged 28.7% year-on-year, while retail values soared 28.1%. Meanwhile, average weekly spending online grew 22.5% to £579.6m.

Month-on-month retail sales dipped 0.9% in August. This followed a “strong” 1.1% increase in July due to the good weather. Despite this month’s fall the volume of goods bought stayed high.

A 2.7% month-on-month fall in food sales offset the increases. According to the ONS food sales had returned to a “more normal level” for the time of year after a 2.7% jump in July.

The prices of goods sold in the retail industry slowed to 1.6% last month from 1.8% in July.

British Retail Consortium director general Helen Dickinson said: “While not quite on a par with an exceptional July, these are strong figures well above the annual average and are sustaining the positive momentum we’ve seen in recent months.”

Barclays head of retail and wholesale Richard Lowe said: “The bank holiday weekend boosted last month’s figures on a year on year basis, as consumers shopped online without the distraction of the Olympics. Computers and electronics proved popular as many prepared for the new school year.

“Retailers will now be hoping the sudden seasonal shift in weather will help sales of new autumn/winter collections as we head towards the golden quarter.”