THE Crown Office has been called in to examine allegations that pro-Union campaigners breached electoral secrecy law by examining referendum postal ballot papers to gauge how well the Better Together campaign was doing before the polls had closed.

Complaints were passed to Police Scotland and elections watchdog the Electoral Commission. These arose following comments made by Ruth Davidson, the Scottish Conservative leader and prominent supporter of the Better Together campaign.

Ms Davidson said during TV coverage of the referendum, 45 minutes after the ballots closed, that the No camp had been "incredibly encouraged" by the results of a "sample opening" of the postal ballot that she said had taken place around the country over the few weeks prior to the poll closing.

She said agents were able to "take tallies" of postal ballots "and the reports have been very positive for us".

Complaints raised concerns the information may have helped inform the No campaign's decision to issue the "vow" of more powers for Scotland from the three main party leaders.

Now it has been confirmed the ­Electoral Commission has submitted a report on the allegations to the Crown Office and Procurator Fiscal Service for examination in the wake of The Herald story earlier this week.

It is expected that Ms Davidson will be spoken to about her TV statement.

Asked on timescales for the ­assessment, a source said: "It's like any report to the Crown, it'll take as long as it takes."

Complaints sent to police and the Electoral Commission surrounded agents being able to see the ballot papers and communicate how the vote was going in advance during opening sessions across Scotland in the days running up to September 18.

Elections Scotland guidance on postal votes states it is an offence for anyone attending the opening of postal votes "to attempt to ascertain how any vote has been cast or to communicate any such information obtained".

Failure to observe the secrecy requirement is a criminal offence punishable by up to 12 months in prison and/or to a fine of up to £5,000.

Video footage of Ms Davidson talking about the ballot viewing during televised referendum coverage has been forwarded to both the police and the Electoral Commission.