IS THE flag flying over Montrose town house the Scottish national flag or the international signal code for the letter M?

Some eagle-eyed locals have cast doubt on the flag which they think fails to match official criteria for the shape, colour and dimensions of the saltire.

The flag for the letter M is square with a dark blue background and narrow white stripes that might easily be mistaken as the genuine article.

While flying M above the town house might not be entirely unsuitable for Montrose, flag buffs point out that the national flag should be rectangular, with a white-on-blue saltire which derives its shape from the cross on which Scotland’s patron saint, St Andrew, was crucified.

In 2003, Scotland’s politicians nailed their colours to the mast and specified the precise shade of blue to be used.

The white St Andrew’s Cross should appear on an azure blue background known as Pantone 300 in the international colour coding system.

The MSPs’ recommendation, however, carry no power of enforcement and saltires continue to fly in a variety of shades.

Montrosian Graham Bartram, a vexillologist and vexillographer (flag researcher and designer), who is secretary-general for the Congresses of the International Federation of Vexillogical Associations, said that the true saltire should also have a cross that is one fifth the width of the flag.

He said yesterday that the last time he checked the saltire flying above his home town it had been correct.

The Royal Navy, when visiting a Scottish port, has been known to hoist the readily available M signal as a courtesy saltire.

Tradition has it that in 832 AD, near the East Lothian village of Athelstaneford, a battle was fought which led to the adoption of the saltire as Scotland’s national flag. A joint army of Picts and Scots under the High King of Alba, Angus mac Fergus, was invading Lothian which at that time was still Northumbrian territory.

Angus’s force was surrounded by a larger army of Angles and Saxons and fearing defeat, the king led prayers for deliverance. Angus believed he had received a divine sign when above him, in a clear blue sky, he saw a great white cross like that of St Andrew’s.

The king vowed that if, with the saint’s help, he gained the victory, then Andrew would thereafter be the patron saint of Scotland and his cross the flag of Scotland. Angus did win and the Saltire duly became the national flag.

Divinely inspired or not, records show the saltire in regular use by the 14th century, although not always against a blue background. In fact, it wasn’t until the 16th century that the plain white saltire on a blue field became established. After the Union of the Parliaments in 1707, however, the widespread use of the saltire declined. It wasn’t until the 20th century that there was a resurgence in its use.