I'd say that's true, but it risks getting close to being condescending in a "We're better educated than them" kind of way ( I'm not saying that's what you're personally thinking btw, it's a general statement ) and, while they might not be as well educated as city folk from London, they're not thick, and know when they're being talked down to ( at best ), or ignored at worse.
Instead of blaming less well educated people in Northern towns, it would make more sense to work out why the level of graduates in these places is lower than the cities.
The answers to that are numerous, but, when younger, educated people have to leave those those towns to find decent jobs in the cities, you have to question the policies of all goverments over the last 30 years or so, which have effectively encouraged the migration of people to cities. That's left behind a disenfranchised population who, at least from their perspective, believe the EC does nothing for them, and the party which they'd traditionally vote for, does next to nothing for them as well.