Apologies to the Moderators for posting in RP. Good job I had enough diversion bytes in my tanks to make it to TL !
EDDNR -- was referring to BOAC's post, not that it matters -- it simply sparked of the idea of this separate thread which might be of interest.
Thanks for your comments, though. In my case, contingency, even if I had all of it unburnt at start of destination hold, would typically be, say, 150 kg. That's 4mins 30secs of destination holding at the stipulated 1500ft ; not a lot, then. I frequently get "10mins holding" estimates into LHR, which often work out that way, so I'd frequently be off to my alternate !
In addition, when everyone else is diverting from LHR, the alternates can fill up and/or become congested very quickly ; I've been in that scenario! I remember diverting to LTN one time and parking virtually where I'd turned off the runway -- chocka ! Alternate holding becomes highly likely in those cases, too. If you divert on min fuel and have to hold at alternate, then you're declaring an emergency, are'nt you ? (less than final reserve on landing).