The Scottish Football Association has written to all 93 full member clubs urging them to come clean over whether they have made any non-contractual payments to their players.

STV has obtained a copy of the letter, which was sent to clubs 11 days ago. In it, clubs are asked to declare whether they have complied with Article 12 of the governing body’s articles of association over the last ten years.

Dated March 9, the correspondence from chief executive Stewart Regan gives clubs until Friday, April 6 to send “any written agreement(s) falling within the scope of Article 12.3 which has/have not previously been lodged with the Scottish FA in the previous ten years, in respect of any current or former players of your club.”

Clubs are then warned they could be referred to the organisation’s Compliance Officer, potentially leading to disciplinary sanctions, if “it is considered that the club may have breached its obligations under the articles…” They are also warned they could be punished if they do not reply to the letter as requested.

According to the letter, the request has been made because “it has come to the attention of the Scottish FA that there could be a number of examples of non-compliance with the obligations of Article 12.3.”

STV understands the Scottish FA view the action as a simple housekeeping exercise which will give all clubs the opportunity to admit to any rule breach.

Article 12.3 of the Scottish FA’s articles of association says: “…all payments, whether made by the club or otherwise, which are to be made to a player solely relating to his playing activities must be fully recorded within the relevant written agreement with the player prior to submission to the Scottish FA and/or the recognised football body of which his club is in membership.”

It is made clear that the written documentation required is "including but not limited to all playing contracts, agreements, side letters etc. which relate to payments made to players solely relating to their playing activities".

The Scottish Premier League’s chief executive, Neil Doncaster, and his counterpart at the Scottish Football League, David Longmuir, also received copies of the letter.

The request comes during an SPL investigation into allegations that Rangers paid players outside of their contracts, with their inquiry stretching back to 1998.

The Scottish FA have already stated they have no present plans to conduct an inquiry of their own, as they would be required to act as the appellant body with regards to the SPL’s investigation.

The letter opens: “In light of recent well-publicised events, I would like to take this opportunity to remind clubs of their obligations pursuant to Article 12 of the Scottish FA’s Articles of Association.”

Later in the letter, clubs are asked to send in further information. The first requirement asks for “a declaration signed by the club secretary to the effect that your club has complied, without qualification, with the terms of this article at all times throughout the previous ten years.”

The second request asks clubs to submit any “written agreement(s)” within the last ten years, with regards to Article 12.3, which are not already in the Scottish FA’s possession.