Scottish independence referendum campaigners spent £6.7m
Campaigners spent £6.7m ahead of the Scottish independence referendum, the Electoral Commission has reported.
The UK regulator of elections said 42 organisations and individuals were officially registered as campaigners.
The September 2014 poll resulted in voters rejecting Scottish independence by 55% to 45%.
Campaigners spending more than £250,000 were required to submit an independently audited return to the commission by 18 March of this year.
The two official campaigns, Better Together and Yes Scotland, spent a total of £1,422,602 and £1,420,800 respectively.
The commission said all campaigners were required to submit invoices of more than £200.
However, it revealed that information was missing from Better Together's returns and that it was consulting with both the Crown Office and procurator fiscal office as to whether a legal investigation needed to be held.
In a statement, Better Together said: "The Electoral Commission have been provided with further information in regards to any queries and have been provided with the supporting evidence they require for Better Together's referendum expenditure.
"Any items of expenditure (train bookings for example) for which invoices could not be sourced are supported by bank statements showing this expenditure to ensure transparency in our returns.
"The Electoral Commission are legally obliged to liaise with the Crown Office in this regard. There is no investigation under way."
Political parties who had representatives in the Scottish Parliament were also allowed to spend large amounts of money ahead of the referendum.
The SNP had a limit of £1,344,000 and spent £1,298,567; the Labour Party had a limit of £831,000 and spent £732,482 and the Conservative Party had a limit of £399,000 and spent £356,191.
The Electoral Commission is now preparing a report which could include recommendations on rule changes to spending by campaigners taking part in future referendums.
Prime Minister David Cameron, who is leading the new majority Conservative government at Westminster, has promised to hold a referendum on Britain's membership of the EU by the end of 2017.
|Party spending during independence referendum|
|Scottish National Party||£1,298,567||£1,344,000|