THE Electoral Commission has said it must be allowed to assess the question put to voters in any future independence referendum.

The body has urged amendments to Nicola Sturgeon's Referendum Bill in a letter to MSPs.

The First Minister has said she wants another independence vote by 2021, but this could be set back by the watchdog wanting to assess the wording "regardless of whether the commission has previously published views on the question proposed".

The Bill, as proposed by the First Minister, argues if a question has already been analysed by the Electoral Commission then it would not have to be assessed again.

Under the current plans, the commission would be excluded from assessing the question used in 2014: "Should Scotland be an independent country?"

Writing to MSPs on Holyrood's Constitution Committee, the watchdog described its "important" role in informing a referendum question to make sure any question put to the public is "intelligible".

The submission said: "The commission firmly recommends that it must be required to provide views and advice to the Scottish Parliament on the wording of any referendum question included in legislation under this proposed framework, regardless of whether we have previously published our views on the proposed wording."

The Electoral Commission also suggested an increase in the maximum fines it would be able to impose for financial wrongdoing in the referendum campaign, raising the limit from the proposed £10,000 to £500,000.

The commission wrote: "The maximum fine for breaches of the campaign finance rules (should be) increased to a level that is high enough to have a deterrent effect on all campaigners."

Responding to the proposed changes, a Scottish Government spokesman said: "The Bill makes specific provision for the involvement of the Electoral Commission to consider the proposed referendum question.

"It will be for Parliament as a whole to decide and vote on these matters - both the proposals in the Bill and in any regulations made under it - and we will, of course, listen to all views put forward.

"The 2014 referendum question was proposed by the Electoral Commission and provides a clear precedent for a simple, straightforward and understandable question."

Commenting on the Electoral Commission's submission, Pamela Nash, chief executive of campaign group Scotland in Union, said: "The people of Scotland have already chosen to remain in the UK in a once-in-a-generation referendum so there is no need for this Bill in the first place.

"But if MSPs press ahead with the Bill, it is vital that this important recommendation from the Electoral Commission is actioned."

She added: "Should we ever be in the situation where Scotland's place in the UK is subject to another referendum, to ensure that it is carried out fairly and the result is respected by all, the wording of the question must be looked at again by the Electoral Commission in all circumstances, including if the question proposed is the same as in 2014.

"Crucially, ahead of the EU referendum, the Electoral Commission recommended that a Yes/No-style question be dropped to ensure a more balanced question."