Open source should be the default for software that runs public services

When a government pays for software, the public has paid once. We think it should be able to see how it works, reuse it, and avoid paying again for the same thing in the next city.

Open-source software is software whose source code is published under a licence that allows others to inspect, modify and share it. For public services it offers four things: scrutiny, since errors and bias are easier to find; reuse, since one authority's investment can serve many; independence, since an authority is not locked into a single supplier; and continuity, since the code survives even if a company folds.

The strongest objections are real. Open source does not mean free of cost: maintenance, security and support still need money and skilled people. Some systems, such as those handling sensitive data, need careful access controls even when the code is open.

We would answer that "open by default, closed by exception with a stated reason" is a better rule than the reverse.

What would change our mind: evidence that, across many projects, open publication leads to worse security or higher lifetime costs.