London is easy to get around – we have a Tube map. A simple diagram based on an electrical circuit, designed in 1933, and still in use today. Its diagrammatic principle is ideal for showing connections and the relationships between stations. It’s great for travelling on the tube, but the thing is, when it comes to walking the street, it’s rubbish – and yet we found that 45% of people do exactly that.

Other maps we use are also unsuitable for walking. The A to Z and multimap for example are good for driving, but they do not show the width of roads, line of sight and other details that are crucial for the pedestrian to recognise a road and work out where they are. Add in the wonderfully idiosyncratic positioning of street names – high, low or just missing – and a short walk can sometimes be quite a challenge.

The strength of the tube map, combined with the weakness of pedestrian mapping, produces a distorted sense of distance and direction. Consider that we have 27 million visitors a year who know very little of the city, and the inevitable result is confusion.

Once we’ve taken the plunge and decided to walk, what is around to help? What we found is that there’s no shortage of information, except when it’s needed. In the current congestion charge zone alone, we counted 32 different sign systems before we gave up. They appear in different places, some at junctions, some on routes, some have maps, many just ‘finger posts’. They come in all shapes and sizes, and if they indicate distance it’s in kilometres, minutes, miles, metres and even 1/4m’s.

These diverse sign schemes create unpredictability, which is the greatest enemy of an effective sign system. The biggest problem is that we do not know what to expect, where to look, and whether if we follow one sign, there will be another further down the road to help us reach our destination. There are some good sign systems around, but they suddenly end halfway through your journey. Why? Because you’ve reached a borough boundary, or a different jurisdiction. Is this relevant to the person trying to find their way around? Of course not.

Of the people we asked, only 3.7% actually used any of the different sign systems. Confusion reigns, and little confidence exists. This is a problem for all of us: visitors, Londoners, local councils, central government, and designers.

Any sign system that tackles a city as complex as London needs to understand how we build our geographical understanding. How do we remember or recognise where we are? Primarily, we use landmarks and names. It depends on context – the London Eye, the Pagoda in Kew, a local church, a patch of grass – whatever is distinctive and memorable. London is saturated with these distinctive places and local character – key elements that need enhancing to make the city more legible.

People draw ‘mental maps’ of areas they know, especially when walking. In London these pockets of knowledge are often separate from each other – a result of London’s size and the scattering of tube stations and bus stops (the places we usually start a walking journey). I learnt London using the Tube, and I still get that wonderful feeling when I fit two parts of London together above ground, I’m always amazed by how close they suddenly seem. Indeed, once we draw a roughly 12 to 15 minute walking diameter around the key hubs in central London we begin to see how closely these pockets sit to each other, and how walkable London really is.

How can we shine a light between the bits we know, filling in the gaps, and connecting these pockets?

In the modern city, walking is increasingly seen as a transport mode, like cycling. Transport information at tube stations and bus stops needs to take this into account. Enhancing these modes for the future is something that the Mayor and Transport for London have been increasingly aware of, as we have seen with the improved information for cyclists. Legible London shows that this is now moving forward in relation to walking as well.

If we start to think about designing a system for London, we have to bear some important principles in mind – it must be predictable, easy to understand, and use progressive disclosure – the right information at the right time. Many of these principles are to be found in the 1963 road signs system which has stood the test of time – it is still substantially unchanged more than 40 years later.

Another key issue to look at is: what is needed where? What routes do we need to support, and how do we make the system predictable? We want as few signs in the ground as possible, but as many as necessary, to give people the information they need. The grain is different in central and outer London, but the methodology and predictability of the system needs to be the same. The information for pedestrians should be integrated across all media that people use, from maps and planners to online journey planning and PDAs as well as signs in the ground.

It sounds like a pretty big challenge to get London’s information to connect together, but the general response we have been getting from most people is yes, it could be improved, and yes, we would like it to happen. The Olympics present a fantastic opportunity, because we all want good information provision to be in place. This focus can help people agree the detail necessary to create a system that will stand the test of time.

The Legible London study and exhibition were commissioned by Central London Partnership and funded by Transport of London. The Legible London exhibition is on at the NLA, Store Street, off Tottenham Court Road until March 2007.