Scottish independence: Campaigns chief signed CBI form
The application submitted by the CBI to register as a campaigner against Scottish independence has been made public.
The form was signed by the CBI's head of campaigns and its senior campaigns advisor.
Several organisations quit the business lobby group after it formally backed the "No" campaign.
The Electoral Commission nullified the application after the CBI said it had been signed by an unauthorised person.
A spokesman for the organisation said the form had not been signed by the secretary of the CBI or a person who "acts in a similar capacity".
The application form, which has been published by the Electoral Commission, was signed by CBI head of campaigns Richard Maughan and senior campaigns advisor Jon Harrison.
In an interview with BBC Scotland last month, CBI director-general John Cridland said the application had been the result of an "honest mistake".
Mr Cridland said: "An official in our London office signed what he thought was the regulatory compliance necessary to deal with the CBI's expenditures on things like our events and our dinners.
"But obviously of course it opened a Pandora's box of unexpected consequences and it began to challenge the standing and the reputation of the CBI."
Mr Cridland said he and other CBI board members only became aware that the organisation had registered as an official backer of the "No" campaign when it was reported in the media.
He was also quoted in the Daily Telegraph newspaper as saying the application form had been signed by a "relatively junior" member of staff who had been "operating outside of their authority", but stressed he was "making no criticism of that individual".
The Electoral Commission accepted that explanation, and agreed to remove the CBI from its register "for the only reason" that the business body had not ensured that the person who signed its application was authorised to do so.
John McCormick, electoral commissioner for Scotland, said: "The law, and our own guidance, state who can sign a permitted participant application form.
"In this case, the CBI submitted a form to the Electoral Commission that had been signed by the wrong person and their application is void."
The CBI now says it is neutral in the independence debate.
A spokesman added: "On 1 May the Electoral Commission declared the CBI's application to register under the Scottish Referendum Act 2013 void because the form was not signed by the secretary of the organisation or a person who acts in a similar capacity."
In a speech on Wednesday, CBI head Sir Mike Rake said: "Ultimately, because of the range of unknown and unforeseen consequences of independence, it is difficult to see how independence would be better for investment and for jobs.
"The case has not been made that an independent Scotland would be better for our economy."
His comments were dismissed by Business for Scotland, a group supporting a "Yes" vote in the referendum on 18 September, when voters will be asked the Yes/No question: "Should Scotland be an independent country?"
The group said that "more and more businesses here see the opportunities that independence offers them".
"They see that Scotland's economy will thrive in the hands of a Scottish government that understands its needs," it added.
A number of organisations, including universities, several quangos, the Law Society of Scotland, broadcaster STV and two businesses - Aquamarine Power and Balhousie Care Group - left the CBI after it registered as an official "No" backer.
The BBC had said it would suspend its membership during the campaign period, but later announced that this was "no longer necessary" as the CBI was no longer registered as a backer of the "No" campaign.
It added that it would instead transfer membership to its commercial business, BBC Worldwide.