The elections watchdog has rejected the Scottish Government's preferred question for next year's independence referendum.
First Minister Alex Salmond's proposal for the historic vote is to ask voters: Do you agree that Scotland should be an independent country?
But the Electoral Commission said using the phrase "do you agree" could encourage some people to vote Yes. It said the question should have a more neutral wording, and recommended it be changed to: Should Scotland be an independent country?
John McCormick, Electoral Commissioner for Scotland, said: "We have rigorously tested the proposed question, speaking to a wide range of people across Scotland.
"Any referendum question must be, and be seen to be, neutral. People told us that they felt the words 'Do you agree' could lead voters towards voting Yes."
Voters have a "clear understanding that 'independent country' meant being separate from the UK", McCormick said.
The decision comes on the same day David Cameron told the Commons at PMQs that he "we will not pre-negotiate Scotland's exit from the United Kingdom".
McCormick also said voters want more factual information before the referendum so the commission has called on the UK and Scottish governments to clarify the processes that will follow the ballot, regardless of the outcome.
"We're asking the UK and Scottish Government to provide that clarity and we'll then make sure it gets to voters as part of our public awareness campaign," McCormick said.
The commission also suggests higher spending limits for the referendum campaign than the Scottish Government has proposed.
Pro-independence Yes Scotland, and Better Together, which wants Scotland to remain in the UK, should be allowed to spend up to £1.5 million, double the £750,000 suggested by the Scottish National Party administration.
The amount political parties are allowed to spend should be based on their share of the vote from the 2011 Holyrood elections, the commission said.
This would see the SNP, which won a landslide victory, allowed to spend £1,344,000, while the Greens, who back Yes Scotland, could spend up to £150,000.
These limits would "allow each of the parties to campaign on a similar scale as they did at the 2011 election in putting across their party messages", the commission said.
"The total cumulative value of the limits for the parties that have expressed support for each outcome at the referendum will be similar."
The Scottish Government proposed that political parties represented in the Scottish Parliament spend a maximum £250,000.
The limits would only apply in the 16-week period before the referendum, due to be held in autumn 2014.
McCormack said: "The campaign spending limits we have recommended are designed to ensure there are no barriers to voters hearing from campaigners in what will be a historic vote for the people of Scotland.
"We have listened carefully to the views of the Scottish Government and to campaigners and have set out proposals based on our principles that spending limits should allow effective campaigning for all outcomes, deter excessive spending and encourage transparency."
Scottish Deputy First Minister Nicola Sturgeon suggested that the Scottish Government could accept the commission's findings.
She told MSPs yesterday that ministers would attach "considerable weight" to these.
"There would have to be a very good reason to depart from Electoral Commission recommendations, and any government so doing would have to explain its position to this Parliament," she said.
But the Scottish Parliament has the final say on issues such as the wording of the question when it considers the Referendum Bill.
"The Scottish Government will consider the wording of the question, and indeed other matters relating to the conduct of the referendum, in light of the commission's advice and, of course, the Scottish Parliament will have the final say during its scrutiny of the referendum legislation," she said.
In its report on the wording of the question, the Electoral Commission said that, overall, people found the Scottish Government's preferred question to be "clear, simple, concise and to the point".
People "found it easy to understand and answer".
But the "main issue that arose in the testing related to the perceived neutrality or otherwise of the proposed question and, in particular, the opening wording 'Do you agree'," it said.
Use of the phrase 'Do you agree' was "commonly felt by research participants to be biased towards a Yes outcome and potentially leading people towards a Yes vote", the commission said.
"People said that asking the question in that way implies that Scotland being independent is a good thing because voters are being invited to agree with this view. It can sound like it is seeking agreement by effectively asking 'Do you agree with me?' rather than allowing voters to form and express their own view."
People also felt that the words 'Do you agree' could suggest that "the decision has in fact already been made, or that 'Scotland should be an independent country' represents popular opinion and that the referendum is simply about rubber-stamping that decision".
The commission report said: "People also felt that that 'Do you agree' was biased towards a Yes vote because it is easier to agree with something than to disagree."
Some people "felt that there is an expectation that if you disagree, you need to justify or explain why you have done so".
Some undecided voters felt that the Scottish Government's preferred wording of the question "could give the impression that Yes is the 'correct' answer", the commission said.
"Overall, people's concern was less that this wording would cause errors in how people marked their vote but that it would be more likely to influence those who were undecided, unsure or 'easily led' and were concerned about this."