Shoppers are reflected in a window as they carry bags along Oxford street during the final weekend of shopping before Christmas in London on Dec. 20, 2014. Reuters/Luke MacGregor

(Reuters) - British retailers are optimistic about their prospects for 2015, with a large majority expecting increased sales and higher levels of employment and investment, an industry survey showed on Thursday.

The British Retail Consortium said 76 percent of retailers reported that they expected sales to improve this year, and 78 percent said they were likely to employ more staff.

Just over two-thirds responded that they expected to increase investment levels.

Weak consumer demand was the biggest cause of worry for retailers, followed by business rates tax, the survey showed.

"The retail industry will be doing its part to drive growth in 2015 -- by investing and creating jobs -- but these efforts will be hampered if serious solutions to the burden of business rates are not found," said Helen Dickinson, the BRC's director general.

Britons' spending power has been boosted by weaker inflation, which fell to its lowest level in more than 12 years in November. Consumer confidence has eased since then, however, and data last week showed Britain's economic recovery was not as strong during 2014 as previously thought.

The BRC's survey was conducted in November and accounted for around 18 percent of the retail industry by value.