Is there a difference between a Newcastle accent and a Sunderland accent?

Yes. However, you need to be from North East England to recognise the difference.

I live in southern England. I would not notice any difference between a Geordie and somebody from Sunderland. However, I understand that there are fierce rivalries between those two cities, so be careful if you think somebody comes from the north-east - find out which part they are from before making an unwelcome mistake!

Of course

Yes to the people that live there - however we Scots think that the English are just like the Scottish people but with their generosity stripped away. Ever good a a Gordie to buy their round without being reminding them it's their round? LOL. (Said in friendly banter). Scots, Newcastle and Suthlanders are all thinking the same about the Londoners LOL. The world of the British Government spending fairly on the voters stops near Watford gap and everything North of Watford Gap is "The North" and undeserving of their time or thoughts of fairness.

Aye, boyo.

Why aye. What about Middlesbrough? They all sound the same to my Southern Counties ear.