Would the blue bit have to go? As shown in the image, the Jack has evolved from the marriage of the cross of Saint George and Saint Andrew, on the ascent to the English throne of the Scottish James VI in 1603 and then the incorporation of a hastily configured Saint Patrick's cross in 1801, representing Irish union.
A case remains for the Saint Patrick's cross's continued inclusion, as for almost 100 years, since Northern Ireland opted out of the Irish Free State in 1922, England has clung onto a corner of Ulster. But if Scotland opts out in 2014, on what grounds could we continue to fly its colours as our own?
Cameron might see it as an opportunity to give brand Britain a make-over and get the same designers who did the Olympic logo to reconfigure the flag into a nondescript and slightly confusing symbol that's open to misinterpretation. I can see the Welsh getting upset too once the debate begins – after all they've been overlooked since 1282.
Flag designs on a postcard please...