When it comes to developing the design of the London Tube map, there is no such thing as one small adjustment, says Transport for London (TfL) head of design Jon Hunter. ‘As a product, the Tube map is entirely interconnected, so even a small change can result in large sections of the map needing to be redrawn,’ he explains. ‘Is there enough space on the current map to accommodate the change and, if not, what do we need to move or change to allow it to be included?’

It was a consideration that came into play with the first major Tube extension this century, with the addition of new stations Nine Elms and Battersea Power Station in a move that puts previously neglected south London on to the Tube map.

The new stations are represented by a curving loop already seen in other parts of the map, such as between Liverpool Street and Aldgate. To ensure consistency, strict design standards specify everything from the thickness of the lines and dimensions of the angles to the spacing of the station names.

As well as conforming to these design codes, tweaks to the design must also respect physical boundaries. ‘One of the constraints that we face when adding additional content to the map is the symbiotic relationship with other elements that must appear,’ adds Hunter. ‘For example, the River Thames, other nearby lines and the fare zones, which often combine to determine the eventual design solution. The representation of the Northern Line Extension was created using the existing design elements. The design continually evolves as we consider what additional information would be useful to customers, for example including short walking interchanges between some stations.’

The resulting contemporary design, even when allowing for these changes, is still rooted in the classic and original version of the map designed by Harry Beck in 1933. ‘As a truly iconic design, we seek to evolve the Tube map to best suit the ever-growing size of the network. The recent launch of the TfLGo app provides the same design language in a digital format, but allows for personalisation by the user.’ §