Despite being a major US city, Boston, with its 51 separate higher education institutions, can look and feel like a college town.

It is difficult to square the idyllic vista of trees and neat clapboard houses seen from Roxbury Preparatory Charter School with the stereotype of a deprived American inner city and its associated problems.

But many of the large wooden houses are known as “triple deckers”, with up to six families in a single building. And Boston’s reputation for educational excellence has not extended to its state or “public” school system - in the minds of parents at least.

Although in the last decade Boston has twice been judged to have the country’s best urban schools system, parents flock to charter schools, citing “severe academic underperformance” among local pupils as the reason.

Indeed, many 11-14 charter schools see it as their mission to help pupils leave publicly funded education altogether, with scholarship places in prestigious $28,000-a-year schools the preferred destination for their graduates.

“Even if it means we have to send children to another charter school we’re not going to send them back into the public school system,” says Kyra Wilson Cook, Roxbury’s head of dissemination.

“Mostly because we don’t believe those schools are going to have the kind of results we want.”

But why do Boston’s state schools produce low results? Charter schools blame unions, excessive bureaucracy and a lack of freedom and flexibility.

However, closer inquiry reveals that Boston suffers the same inbuilt problem as English cities where municipal boundaries exclude surrounding affluent middle class suburbs that would push up average test results.

This doughnut effect is intensified by city families sending their children to more attractive-looking suburban schools.

Now charter schools are providing those who believe conventional state schools are failing with a new escape route.