Retailers suffered sluggish sales in October as consumers apparently slowed down on spending ahead of promised Black Friday bargains, official figures suggest.

The Office for National Statistics (ONS) said the quantity bought in the retail industry is estimated to have decreased by 0.6% compared with September.

Year-on-year sales registered a 3.8% increase, but this is down on the equivalent figure of 6.5% last month.

The ONS said the retail sector is continuing to grow with October seeing the 30th consecutive month of year-on-year increases.

Ian Gilmartin, head of retail and wholesale at Barclays, said: "October saw mixed results in the month for retailers after the strong performance we saw in September.

"Unseasonably warm weather added pressure to footfall and intense competition in the food and drink sector contributed to continued food deflation, so it's no surprise that growth is slightly lower.

"It's also natural to see a pause before we hit Black Friday and the Christmas trading period."

However, Mr Gilmartin said research suggests UK retailers are confident about the upcoming season with 79% expecting revenues to increase compared with Christmas 2014.

He said: "If retailers can get their Christmas plans right, including managing their level of discounting around Black Friday carefully, the industry should still enjoy a positive end to the year."

ONS head of retail sales statistics Melanie Richard said: "Despite the fall on the month, the longer term trend is one of growth in the retail sector.

"The figures show that, over the last year, the amount of goods shoppers have bought has increased at a much higher rate than the amount they've spent. This is likely a result of store prices continuing to fall."

The ONS said average store prices, including petrol stations, were down 3.3% on October last year, the 16th consecutive month of year-on-year falls.

The amount spent in the retail industry increased by 0.5% compared with October last year, and decreased by 0.7% compared with September.

The value of online sales increased by 11.2% on a year ago and decreased by 0.8% compared with September.

Ian Geddes, head of retail at Deloitte, said: "Despite the expected growth in retail sales volumes year on year, October's sluggish retail sales growth in value could be down to consumers waiting to bag a bargain over the next few weeks.

"Although the prolonged discounting period can be a challenge, retailers may feel obliged to compete in order to maintain market share and retain customer loyalty.

"For this reason, we are likely to see another record-breaking weekend, despite some larger retailers having a lower level of participation."