Some 2-3 weeks ago you ran a letter about problems with diesel fuel blockage caused by the addition of biodiesel to standard diesel and lack of use of the vehicle. I have a smallholding and two tractors running on red diesel. One tractor is kept garaged, the other kept outside. I recently started having problems with starting the tractor left outside, commensurate with fuel starvation and it followed a very wet period we have had here in North Wales. When I checked the fuel filter it was slimy, and I just thought that it was a build up of gunge or possibly the problem you highlighted in the DT letters. However this week I was discussing the problem with my neighbour's son in law who works in the marine industry servicing boats and he remarked that they had lost a big tank of red diesel due to diesel bug that is something I had not previously heard of.

His description of the problem was similar to what I had experienced with my tractor. So today I did a search to find out a bit more and I came across this link that you may find interesting. www.howcleanisyouroil.com/DIESEL-FUEL-BUG. Reading the article explains the conditions that need to be present for the bug to multiply and I suspect that my problem in the problematic tractor is that of diesel bug as the tractor kept indoors running on the same red diesel stock starts first time.