Highlights of Sunday's trip to Newcastle ...

Great Heck Patrick 4.8%, an Irish Stout which pours jet black with a tan head. Aroma, cocoa & malt. Taste is roasted malt, chocolate, coffee, lactose, vanilla and nuts. Very nice. (Newcastle Tap).

Long Man Old Man 4.3%, an old favourite and premium (or old) ale. Pours near black with a tan head. Aroma, malt & toffee. Taste is malt, chocolate, coffee, toffee, dark fruits & spice. Delicious. (The Victoria Comet).

Gaz if your going Oldham sunday I've got a couple of bottles of
Springhead Brewery Robin Hood you can have. I've tried it a few times and
it's not for me.
It's a 'smooth chestnut butter with plenty of hops and malt'

Sadly, can't get there on Sunday, long standing Diamond Wedding lunch appointment. Nice offer though.

I prefer margarine...

A few recent highlights ...

Starting with a couple of very enjoyable repeats (in the Lower Angel, Warrington) ...

Tiny Rebel Stay Puft 5.2%, the excellent marshmallow porter.
Empire Rum Porter 4.7%, a very nice smokey rum infused porter.

And a new one in Little Plough, Doncaster ...

Kansas Avenue Tornado Alley 3.7%, a copper coloured best bitter which has a malt & caramel aroma. Taste is similar with toffee and a hint of spice. A decent best bitter.

The next Wetherspoons Real Ale Festival will (officially) run from Wednesday 9 October until Sunday 20 October 2019.

40 ales will be available this time, marking 40 years since founder Tim Martin opened his first outlet in 1979. 35 UK and 5 International breweries will be represented.

Not wishing to start WW3, I take Ordinary bitter to mean abv up to 4.1% ...
Best bitter from 4.2% to 4.7% ...
Premium bitter from 4.8%
Why is 3.7% bitter, best bitter?

Some light reading on the subject https://en.wikipedia.org/wiki/Bitter_(beer) https://www.winning-homebrew.com/Best-Bitter.html Whilst looking this up on the all seeing Google eye, an advert popped up for Co Op best bitter at 2.8%. I would let the Grandkids have that with their school pack up. (just kidding Social services)

Some light reading on the subject https://en.wikipedia.org/wiki/Bitter_(beer) https://www.winning-homebrew.com/Best-Bitter.html Whilst looking this up on the all seeing Google eye, an advert popped up for Co Op best bitter at 2.8%. I would let the Grandkids have that with their school pack up. (just kidding Social services)

Looks like the boundaries change or people make mistakes (me included) ... the 'light reading' offered above has best bitter from 3.8% but that still wouldn't cover this one ... perhaps it's simply my bad.

Well folk march to the bar and say a pint of your best bitter landlord.
Thinking it means your finest ...
Only a few know roughly what best bitter is.

I deduce from the guff above (not your post) that best bitter is open to translation. And with most thing concerning the palate it may come down to ones own preference (taste) I always thought that a pale ale was just that and not a bitter. But most traditional pale ales would have matched the bitter description. If you stick to the best bitter tag my personal favourite would be the redefined Barnsley BB brewed really well by Acorn and by Stancill.

... and only 3.8% ...

The Acorn version is much improved at the Little Plough these days

There as been a trend in recent times to lower abv to lower tax paid on said ale.
And yet not lower the price to the consumer.
Some like Carling (lager granted) even labelled their abv as at least 0.2% higher than it actually was.
And they even said that that is what their customers preferred, in their defence.
I thought fraud was fraud.
Anyway the point I am trying to make is that apart from smaller brewers that like to brew strong ales and charge accordingly, the larger brewers have shifted what may have been best bitters into the (ordinary) bitter bracket.
A case in point being John Smiths.
And yet call it a premium beer.
Nonsense!!