Plans have been announced to try and spruce up a subway next to Baker Street station that has a curious secret within it.

People entering Baker Street station often cross the busy road outside by a set of traffic lights — that were only installed a decade ago — preferring to avoid the long-serving, but run down subway that runs under their feet. A delay of a few minutes seemingly preferable to the steps and sometimes noisesome tunnel.

Part of the reason for the lack of tunnel use is probably down to a simple distaste for tunnels — but also, certainly for visitors leaving the station, that the tunnel is not particularly obvious. In fact, for the northern side, it’s pretty well hidden from view in a cluster of small shops.

There were plans back in 2008 to do away with that cluster of shops and build a much more obvious entrance, which was tied to plans to improve platform access to the Met/Circle line platforms below. Those plans were put on hold.

Now a local business action group, and TfL is proposing a smaller scale project that will initially see the tunnel closed overnight to dissuade night time dwellers, and eventually a bit of a refurb.

However, what lies down here also is a long since closed off entrance to the tube station itself — sealed off behind a metal barrier, yet just about visible if you stand on the nearby steps and on tip-toes.

If you do peer over the top, then you’ll see a tube-tiled corridor leads off, with two sets of stairs easily seen heading down, and an another corridor at the end. According to the planning documents, the two staircases lead down to the Circle line platforms, with the corridor running under the street to a set of stairs on the opposite platform.

Although I haven’t been able to find out when the entrance closed, it seems likely that it would have been at least when ticket barriers were introduced, as otherwise people have an easy way to bypass them.

So there you are, a little sealed off bit of tube tunnel that is just about visible, if only you had known about it. And now you do.