Good debate... Getting some interesting reactions...!
I disagree with one thing that Antigua has been interpreted as saying (and so I may disagree with him) - the requirement to land with Reserve, does, IMHO, leave you with sufficient fuel to Go Around, Visual Circuit / TIGHT radar circuit, land before tanks dry i.e. without a call, the way I would play it always leaves the option for the Go Around.
Having gone around, the situation is now "urgent" - the next landing must be made - hence the "Mayday". The PAN option defines another specific fuel state that got skipped here, but may be made where there is a little more fuel...
As I said before, lets try and concentrate on "safety". Issuing a Mayday does not imply a dangerous situation in itself, its just a radio call. Its "grave & imminent.. threatens.. immediate assistance required..." i.e. I would expect ATC at this stage to keep a runway clear for you. The commercial fall out of this may get the policy changed, but I don't think it has (yet) occurred in recent times.
Chances of this happening:
1. How often at LHR do we get to an approach where we land with reserves only, or a little more? Very rarely - the times I've "committed" to LHR (gone below fuel sufficient to divert) is probably ~5 in as many years of SH operation based there, in each case landing comfortably above reserve (I think only 1-2 of these would have required a PAN if we went around)
2. How often, of these rare occasions, require a Go Around? Very few... and if you do as Antigua did, still less because ATC were forewarned (if unhappy).
As said elsewhere, very different from the certain other carrier regularly landing at LHR without fuel to do a Go Around and saying nothing...
NB Our rules used to say that as we "committed" to LHR, consideration be given to informing ATC. I still do that - it gives an ATC an idea, well in advance, that fuel is not that fat, and more importantly, if others did it, lets ATC see the day building up where "everyone" has committed! What's more, when I make that call, ATC seem to understand what "committed means"...
NoD