Bertie Portelli (August 10) pointed out that Britain's national flag is "only referred to as the Union Jack when it is hoisted at sea".
But it is not so. Parliament decreed in 1908 that "the Union Jack should be regarded as the National flag".
Before that date it was frequently described as both Union Jack and Union Flag, and neither was wrong, nor is either of them wrong today. The Merchant Shipping Act refers to "the Union flag (commonly known as the Union Jack)".
A jack is usually a small flag (on a jack staff) at the bow of a ship and there are times when the Union Jack is flown as a jack.
One school of thought is that the name has nothing whatsoever to do with jacks or jack staffs, but relates to King James (Jacobus), who is generally credited with uniting his kingdom, and caused the flag to be designed.
The BBC tends to favour the term Union Flag - but for no other reason than to stop people like Mr Portelli writing in to tell them they've got something else wrong.
Flag or Jack, it makes no difference.