The National Institute of Economic and Social Research (NIESR) released its estimate of gross domestic product (GDP) for the U.K. on Wednesday. The GDP estimate rose by 0.3% in three months to April, after a 0.4% growth in three months to March. The previous figure was revised up from a 0.3% growth.

"UK economic growth continues to be subdued compared with the rates we saw at the end of last year. Some of this slowdown is undoubtedly a result of heightened uncertainty around the impending EU referendum, and so is likely to be temporary should the UK decide to remain in the EU after June 23rd," Jack Meaning, NIESR Research Fellow, said.

The NIESR yesterday lowered its GDP growth forecast for the U.K. If Britain remains in the European Union (EU), the U.K. GDP will be expected to grow 2.0% in 2016, down from the previous estimate of 2.3%. The NIESR expects the U.K. economy to expand at 2.7% in 2017, unchanged from the previous estimate.