Scottish independence: Who is Scotland's 'silent majority'?
David Cameron wants the "silent majority" who support Scotland staying in the UK to speak up.
He thinks "the noise of the Nationalist few" is already well known, but there is a quieter, less visible pro-Union majority who need to start speaking their minds.
Is he right? Is there a "silent majority" in Scotland and, if so, who are they, why aren't they speaking up, and will they decide Scotland's 18 September independence referendum?
And also, these words have been used by politicians of yesteryear, but by whom and why?
Where did the phrase come from?
It dates back to the 19th century and wasn't connected to politics.
The words "joined the silent majority" were a euphemism for being dead, like "gone to a better place" is used today.
Who first used it in politics?
Its use in politics was popularised by US President Richard Nixon who, in 1969, appealed for the support of the "silent majority" in the USA who didn't demonstrate against the Vietnam war, join the 1960s counterculture, or take part in public politics.
After the speech, Time magazine named "middle America" its "man of the year", and publisher Roy E. Larsen wrote: "The most striking new factor (in 1969) was the emergence of the so-called 'Silent Majority' as a powerfully assertive force in U.S. society."
Who was Nixon getting at?
Nixon was attempting to contrast his "political realism" with what he, and what he believed a "silent majority" saw, as the "flower power" idealism of a vocal minority.
The American president believed a "silent majority" disagreed with 1960s counter-culture figures like John Lennon and his wife Yoko Ono.
Why is Prime Minister David Cameron using the phrase?
Strathclyde University politics professor John Curtice believes the prime minister's use of the phrase is an "implicit recognition" that "No" supporters are less likely to take part in the referendum campaign, in comparison to a highly visible and passionate "Yes" side.
He said: "'No' supporters are much less active in terms of campaigning, going on the web, and knocking on doors.
"They are 'silent', relatively speaking, in comparison to the 'Yes' side."
But why would this be - do "No" supporters not believe in the Union as much as "Yes" supporters believe in independence?
Prof Curtice said: "The 'Yes' side are so passionate because they have probably believed in independence for their whole lives, whereas the 'No' side probably wish the referendum wasn't happening.
"They might be less enthusiastic campaigners, but that's not to say they're less likely to vote."
So, who might the "silent majority" in Scotland be?
Prof Curtice says they are probably at the older side of the age scale, probably women, and most likely indentify themselves as Scottish and British, rather than just Scottish.
Mr Cameron is keen to deliver his message to what he sees as the "silent" supporters of the Union.
Interestingly, after Nixon's "silent majority" speech 45-years-ago his approval ratings, which had been hovering around 50%, shot up to 81%.
Will David Cameron's speech have a similar effect for the "No" side in the referendum? Well, we'll just have to keep an eye on the polls.