Feedback to mudlarking comes in all guises and this from David Rhys Jones particularly amuses me.
 

Tony

LinkedIn asked if I knew you and produced your structure in the Thames by way of introduction.  I was as puzzled as TfL.    

Should you have a heatwave, the flow in the Thames is negligible. Most of the water has been syphoned off to allow the inhabitants of the Metropolis to cavort with partners in cool showers. Should you drop a fag packet or corpse in the Thames at high tide, it will reappear a few feet further down 11 hours later. The temperature of the Thames will be only marginally lower than the temperature of the less privileged inhabitants.  As far as cooling the Tube is concerned, I would not hold out too much hope.

Should you wish to promote other mad schemes, I hope you would consider me as a participant.  I feel more than qualified.   


I will of course take David up on his kind offer - as I have had the pleasure to do so often in the past - and I much look forward to testing his theory on cadavers. 
 
However in the meantime I considered it worth re-investigating the causes of the heat in London Underground tube tunnels and making sure that cooling the clay with my contraption could offer long term benefits, regardless of the climatic and climactic events above.
 
Unsurprisingly I find Sharon Duffy has the detailed requirements of tube cooling at her fingertips, all succinctly captured by IanVisits.