It's staggering how many times people use that phrase and then follow it with utter fallacies - but, hey, makes for a good soundbite!
30 seconds on Google found:
ST George’s Day is an important day of celebration in the United Kingdom. Also known as the Feast of Saint George, here is everything you need to know. When is Saint George’s Day? The feast d…
www.thesun.co.uk
Can't get more 'mainstream' than Murdoch's biggest paper.
The flag of Saint George - a red cross on a white background - is England's national flag.
metro.co.uk
The Metro has huge reach, which must make it 'mainstream' in many eyes.
The patron saint day falls in April each year, but how is it celebrated around the world?
www.telegraph.co.uk
Another, big selling, broadsheet 'mainstream' paper
English Heritage pauses its pageantry for online trail from Roman solider to patron saint
www.theguardian.com
Coverage from the 'other' side of the political spectrum...
https://www.bbc.co.uk/newsround/17816642
One for children from the BBC that day - Perhaps a good place to start?
Most TV news was (and is still) on a rolling cycle - it's almost as if they had a bigger story to focus on that day. That said there were several packages produced on many regional TV News outlets on both ITV and BBC that day.