BERLIN (AFP) - German Chancellor Angela Merkel stressed on Wednesday (June 22) on the eve of a historic British referendum on membership of the European Union that she hoped voters would opt to remain in the bloc.

"Of course I want Britain to stay in the EU but the decision is with British citizens," she told reporters after talks with Polish Prime Minister Beata Szydlo.

Ms Szydlo said she also "strongly hoped" that Britons would choose to stay part of the 28-member European Union.

She said the bloc would "respect any outcome" of Thursday's referendum but added it "must do everything in its power to prepare to strengthen the EU".

"That is our biggest concern," she added.

"The European Union should continue to develop, and should continue to act with unity and decisiveness."

Dr Merkel has repeatedly expressed her support for Britain remaining in the EU, with polls showing the referendum's outcome on a knife-edge.