The precise wording of the question that voters will be asked when an in/out referendum is held on Britain's membership of the European Union needs to be changed - because too many people do not know the country is already a member.
The EU Referendum Bill proposed by Tory MP James Wharton, and backed by David Cameron, suggests the question should be: "Do you think that the United Kingdom should be a member of the European Union?"
However the Electoral Commission has said he should consider changing it to: "Should the United Kingdom remain a member of the European Union?"
In a report published on Tuesday the Commission said: "The research showed that a few people did not know whether or not the UK is currently a member of the EU and this presented a risk of misunderstanding."
Wharton said his "initial reaction" was that there was no need to change the question but said he would "reflect" on the report.
Jenny Watson, Chair of the Electoral Commission said: "Any referendum question must be as clear as possible so that voters understand the important choice they are being asked to make. This is why we have rigorously tested the proposed question and have taken voters' responses and understanding into account in developing alternatives.
"We found that a few people did not understand whether or not the UK was a member of the EU. Providing enough information to make this clear to people creates a risk of a perception of bias for any question which offers 'Yes' and 'No' options.
The Bill returns to the Commons for further debate on Friday November 8.