THE FOREIGN and Commonwealth Office is facing fresh criticism over its behaviour during the referendum, after warning foreign diplomats in London about the hazards of independence.

The SNP called the activity underhand scaremongering, while the UK Government insisted there was nothing unusual in explaining its position at home and abroad.

Papers released under Freedom of Information show that in mid-January, LibDem Scottish Secretary Alistair Carmichael and Tory Europe minister David Lidington briefed members of the Diplomatic Corps on independence ahead of publication of a critical UK Government report.

The briefing on the "Scotland Analysis: EU and International Issues" paper produced by the FCO took place in its "Entente Cordiale" room.

An email to diplomats before the meeting said UK ministers wanted "to hear your government's views on this very important issue".

Two weeks later, on January 28, a member of the FCO's "Devolution Unit", which was ostensibly created in 2012 to help further Scotland's interests abroad, briefed a diplomat at the Russian Embassy at Russia's request, and handed over a copy of the same critical report.

The document warned an independent Scotland would struggle to join the EU; face a "significant financial burden" to set up a diplomatic network; and receive less EU funding outside the union.

UK posts in Europe, the Americas, Australia and New Zealand were also urged to circulate the paper "as soon as possible" and feed back reactions to the Devolution Unit.

In recent months the UK government has briefed foreign powers on Scottish independence in an apparent search for allies against a Yes vote.

Downing Street officials have held talks with counterparts in Moscow and Madrid on the issue.

Both Russia and Spanish governments are worried about their own separatist movements.

The actions are in spite of David Cameron insisting that September's decision is purely "a debate between Scots", the argument he uses for refusing to debate with Alex Salmond on TV.

SNP Westminster leader Angus Robertson said the latest material was "further proof of Project Fear's scaremongering agenda".

He said: "The Devolution Unit is meant to be promoting Scotland internationally but instead is doing the exact opposite - briefing behind the backs of the people of Scotland.

"It is shameful the Prime Minister refuses to debate in front of the people of Scotland, but he and his Westminster colleagues are perfectly willing to lobby against Scotland's interests to foreign governments."

The UK Government said it was perfectly reasonable, and unexceptional, for it to argue its case for the Union, just as the Scottish Government made its case for independence.

A spokesman said: "This story is simply rubbish."