I was travelling on Virgin Trains over the bank holiday, and thought I'd left my return ticket on the outward train. Calling their customer service centre, I was shocked to hear that they don't re-issue tickets in this situation. Apparently my £70 hadn't purchased a seat on the train at all, it had purchased a small piece of printed card. Their outrageous policy was (and is) that I would have to buy a replacement one-way ticket – for another £70.

Unfortunately, a similar but much more expensive double-charging scheme has been in place for years for government-collected data, such as maps, weather and hydrographics (rivers, tides and floods). After all, if our taxes paid for the collection, one would have thought that meant that we could have access to it. Right?

Until 1999, the Ordnance Survey, the British Government's mapping arm, was funded by the taxpayer to make detailed maps of the entire country. These days, they sell limited-use licences to this national asset on a "cost recovery" basis. So, having paid my taxes, when I buy an OS map to go walking in the Lakes, I have the privilege of paying again.

Maps underpin many useful services we take advantage of today. From travel directions to house prices, much of the information we care about has a geospatial element. The effect of restrictions on mapping data availability are easily demonstrated.

MySociety, the digital civic and community activists, did a very interesting study to show, for a few given starting points, whether it would be quicker to take a car or a train to any location in the rest of the UK. Dead handy, and useful input in discussing and formulating transport policy. So can we now go to a website and make a similar map for where we live? No, because the Ordnance Survey data they used is not freely available.

In the US, by contrast. geospatial data collected by federal agencies are placed in the public domain. This allows the creation of cool, free-to-access services such as gsmloc.org, which is building a comprehensive database of GSM cell towers to allow people to locate themselves without a GPS, and Gutenkarte, a weird combination of Project Gutenberg e-texts and maps which shows you all the geographic locations mentioned in a particular book. Check out Around the World in 80 Days.

So what might happen if we adopted the American approach? A lot more than a few mash-ups.

A study in 2000 estimated that, although the US Government spends twice as much on data collection as the EU countries, but the economic value generated by businesses using it was more than ten times greater – €750 billion. That's billion, not million. Was the analysis done by self-justifying American civil servants or biased open-geodata activists? No, it was done by the EU itself. You would have thought that most governments would jump at a share in a multi-hundred-billion-euro fillip for their economies.

A further irony about the short-sighted "cost recovery" policy is that, again using the Ordnance Survey as an example, 60 per cent of its data sales are back to the Government itself. This is not cost recovery, it's merely moving cash around the system. Although free and open data distribution would mean the Survey would need explicit funding, the increased tax revenue from the economic activity generated would more than pay for the additional cost (again, according to the EU study). That's joined-up government. We have some of the highest quality mapping data in the world; the possibilities are limited only by the imagination.

Natural justice and hard-nosed economics agree – Ordnance Survey and other government data, in open formats and under open licences, should be made available, free to all.

Gervase Markham works for the Mozilla Foundation, a non-profit organisation dedicated to promoting choice and innovation on the internet. His blog is Hacking For Christ

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