LAWYERS have warned that allowing same-sex partners to upgrade their relationship to marriage without a ­ceremony could open the door to ­identity theft.

The Faculty of Advocates has proposed that special criminal sanctions against fraudulent behaviour be added to new regulations allowing the old civil partnerships to be converted to the same status of relationship heterosexual couples enjoy.The first same-sex marriages are expected to take place this autumn after legislation was passed at Holyrood.

In a response to a consultation on the rules, the body stressed that marriage always required the couple to be present to avoid impersonation. However, civil partners can apply for an upgrade to any registration office without actually attending a ceremony where they are both present.

The faculty said: "Simply because the parties seeking to be married under the draft regulations do not participate in a ceremony should not diminish the legal protection of marriage. There should be criminal sanction for fraudulent behaviour in this connection."

The proposed rules say applicants must attend a district registrar "in person".