What's the longest A-road in the UK?

There must be a few A roads up in Scotland that must be pretty long. The A9 for instance

that's what google maps reckons, anyhow. and google is all-knowing.

A9 - Bridge of Allan to Thurso 247 miles google say. That distance would get you from Bath to somewhere nice in France

The A34 is quite long I think

There's an awful lot of the midlands to get through. even then I think it'll struggle do better the wild expanses of Scotland...

...but not somewhere Nice

990 miles.  

how's about when you find yr answer you set out on a challenge to ride it in the continuous fashion it deserves: no stopping! 247 miles in one go: that's some decent points in the metric century...

 to Nice… It's warmer

So how many cafe stops would that cover? a fair few me thinks..
Would be great to do it non stop tho with a massive cake at the end!

How about the ancient A5 that runs from North Wales and peters out somewhere just on the outskirts of Londinium?

 Holyhead to London is 288 miles taking the new more direct route, and the A5 goes all over the place in Wales, but it isn't continuous anymore cos it becomes the M51 for a while near the Welsh border

I'm thinking they might be nicer on the Nice run too… there'd certainly be more of them. 

The A38 is the longest A road at 292 miles

http://en.wikipedia.org/wiki/A38_road

"At 292 miles (470 km) long it is the longest 'A' road entirely within England, and in the United Kingdom as a whole second only to the A1." Says Wikipedia.

So it's not even the longest, but it becomes the M5 for part of the way - so you couldn't actually ride all of those 292 miles anyway. The same goes for the A1.

You could ride the full 274 miles of the A74.