The National Institute of Economic and Social Research (NIESR) lowered its U.K. growth forecasts on Tuesday. Britain's economy is expected to expand 2.4% in 2015, down from its previous forecast of 2.5%, and 2.3% in 2016, down from its previous forecast of 2.4%.

"Domestic demand will continue to be the main driver of growth this year and next as households take advantage of purchasing power improvements from the low inflationary environment and firms continue to invest," the think tank said.

The unemployment rate throughout the rest of this year and next year is expected to be 5.25%, the consumer price inflation is expected to increase rises from close to 0.0% in 2015 to 1.1% in 2016, while the Bank of England is expected to start raising its interest rate at the start of 2016 and then to hike gradually by 50 basis points a year, reaching 2% by the end of 2018.