July saw the national vacancy rate increase to 10.3%, the highest in four years, the industry body reported.
The number of people using high street stores also fell to the lowest level since 2012, as footfall dropped 1.9% last month.
Helen Dickinson, chief executive of the British Retail Consortium, said retailers had faced a "challenging environment".
"High streets and town centres play an important part in our local communities, and we should be concerned by the rise in empty store fronts," she said.
The figures showed that high street footfall declined by 2.7% last month, while footfall at shopping centres fell by 3.1%.
Retail parks fared better, with a 1.2% increase in footfall.
Diane Wehrle, marketing and insights director at Springboard, said the rising vacancy rate "highlighted the ongoing challenges faced by bricks and mortar destinations".
She added: "Consumer demand is ever more polarised between convenience and experience, and the stronger performance of out-of-town destinations reflects the fact that retail parks are successfully bridging the convenience-experience gap.
"They not only offer consumers accessible shopping environments with free parking and easy click and collect opportunities for online purchases, but many also combine this with an enhanced experience that includes coffee shops and casual dining restaurants, and some also have leisure facilities.”
Ms Dickinson urged the Government to take action to relieve the pressure on the high street.
"Currently, retail accounts for 5% of the economy, yet pays 10% of all business costs and 25% of all business taxes," she said.
"The rising vacancy figures show this is simply not sustainable. We need an immediate freeze in rates, as well as fixing the transitional relief, which leads to corner shops in Redcar subsidising banks in central London."
Last month was also the worst July on record for year-on-year growth in total retail sales.
Figures from the BRC-KPMG retail sales monitor published earlier this month showed sales edged up by just 0.3% year-on-year in July, compared with an increase of 1.6% in July 2018.