The Union Jack will have to be dumped as Britain’s national flag if Scotland votes to separate, the Government’s official advisers warn today.

One leading expert described Whitehall as ‘terrified’ and ‘woefully unprepared’ for the risk of losing an iconic UK emblem. Another key adviser, Lord West, said it was ‘a nonsense’ to suggest Scotland’s saltire cross could remain part of the design.

The Government’s main advisers on flag policy are the Parliamentary Flags and Heraldry Committee, and the Flag Institute.

Lord West, deputy chairman of the committee, said: ‘In the event of a Yes vote I cannot see how you can save the flag of the United Kingdom.’

Charles Ashburner, of the Flag Institute, described Whitehall as ‘woefully unprepared for the flag-related consequences’ of the Scottish poll. ‘Everyone in Government seems terrified of taking this on,’ he said.

Pictured below are four flags which Mr Ashburner said might, with some possible tweaks, be suitable replacements for the Union Flag.