26th. Middlesbrough
"The Teesside twang is softer than Geordie, but the rich ‘Boro accent is gradually getting more standardised and Southern."
To which the standard Teesside response is simply:
'Ow, yer 'avin' a laff aren't yer, yer fuckin' doyle.
Middlesbrough has a weird mix of North Yorkshire, Durham, Scots, Irish and Scouse. This is a legacy of its comparatively young age (founded around 1830), and its rapid industrial growth, bringing in people for construction and heavy industry. Teesside is pretty the only place other than Liverpool where the Ken Dodd song "Where's Me Shirt?" doesn't sound too out of place.
In fact, the test of a north-eastern accent is to get the speaker to say the words "purple work shirt". The more Scouse it sounds, the nearer the Boro you are, pretty much.