It might sound like a rather obscure sort of event that just a few people would be interested in – yet Londoners have leapt at the chance to walk through the Thames Tunnel at Rotherhithe this weekend.

Tickets for the evening and Saturday visits were sold out almost as soon as they were announced – with the phone line and (decrepit) website suffering under the load of requests. People are now begging for tickets almost as if they are trying to attend a pop-concert.

Thames Tunnel Ticket Touts could make a fortune tonight!

This level of interest in our deep subterranean world shouldn’t really surprise people though – as most of us have a weird fascination with the hidden and mysterious. Even the most disinterested person is going to be mildly curious in seeing what lies beyond the dark voids they occasionally see in the tunnels on their daily commute.

I have a long habit of trying to get into subterranean locations – sometimes with success – and also do a little lobbying on trying to get places opened up where I genuinely think it is possible.

That latter part has been singularly the most disappointing though – as people cry that health and safety is a worry (rarely is) or that no one would be interested (oh, boy are they interested!).

It’s even worse when I don’t even get a reply though – as then I can’t be sure if an idea was evaluated and rejected – or simply thrown in the bin without consideration.

An example of the later would be an email I sent to the DLR last year when the Xmas closure of Bank station was announced. The proposal was simple. It is just about possible to walk onto the Bank line from a side road just before it dips into the tunnel, so why not open the tunnel up to the general public to walk down over the Xmas weekend before the engineering works started?

I just knew that hundreds, if not thousands of people would have leapt at such an opportunity. Not because the tunnel is historic, but because the opportunity is rare, and the walk would be a singularly unusual event to take part in.

No reply – not even a “don’t be stupid, don’t you realise there are a hundred and one reasons why that can’t be done!”

The Thames Tunnel tour will also include a recreation of the Funfair element, but that is a mere sideshow for most people who seem to be going down under the river. It is the tunnel that is the main event here, so other opportunities to open tunnels shouldn’t be reliant on being able to put on a big show. The tunnel is the show!

Maybe the huge demand for tickets to the Thames Tunnel will encourage more openings like this where possible?

I do appreciate the problems in opening subterranean venues though – the organisation, the volunteers needed, the inevitable worries about insurance and crowd control – not to mention ensuring there are no trains using the tunnel at the time!

For that reason, despite people expressing hopes that the Thames Tunnel tour will happen again, I suspect that repeats will be unlikely, simply because you are asking train passengers to lose a fairly important cross-river link. We shouldn’t forget in our desire to visit these places that they have a primary function, and being a tourist attraction isn’t it.

I wont mention details in case plans are being plotted, but I did get a “hmm, interesting” from a suitably connected person at London Underground a year ago for a proposal to open up a bit of abandoned station and a tunnel for a weekend in a way that got around most of the health and safety worries that come from having loads of people in sometimes constrained areas.

Fingers crossed that it happens, and even if it doesn’t, at least I know someone read the email and considered the proposal. That simple act is often worth the effort, even if nothing comes of it in the end.