Could you clarify how the vast majority of people in the world who will never set foot in Peterborough (including me) should interpret that?

From the vantage point of Cambridge it has a reputation as a shithole, but I haven't been there either so would also like to know.

The county council covering the Cambridge area is actually based in Peterborough, and so effectively controls a lot of the countryside around Cambridge, as it is in charge of transport. So arguably the lack of development could be their fault as well.

Supposedly the government is plan is to reduce everywhere to one layer of local government (currently Cambridge is covered by both a county and district council). TBH the areas which are currently unitary seem to work a bit better but there's still massive opposition to building.