This seems as good a place as any to ask this question. I was aware it's often cheaper to get tickets from ex-EU destinations - mostly for commercial reasons (ie why fly BA via LHR when you can fly somebody else direct? The price has to be competitive to capture the traffic, etc).

But I wasn't aware at just how stark the difference can be.

I'm looking to fly from LHR to LAX in September, likely in WT. Currently, the cheapest possible price - either direct or indirect - comes in at circa £760. This seems like a lot and so I've been biding my time for a sale that involves my dates.

I happened to check prices ex DUB and the difference is staggering - it starts from just £410. £350 cheaper - for the same dates, the same flights out of LHR, plus the additional flights from and to Dublin.

How can this difference be explained? Nobody flies direct to LAX from DUB, infact arguably BA have the best routing via LHR anyway. The APD is lower, which will be some of it, but wow, £350 cheaper?!

I'd be amazed if there was even £350 of margin in a £759 economy fare for BA let alone when you add in the costs of the DUB to LHR bits.

If BA can make money flying people from DUB to LAX via LHR for 400 quid return surely at some point we'll see similar fares (adjusted for APD obviously) for us Brits? Heck I'd take something starting with a £5 at this point let alone the £4....

At the moment its looking like a no brainer to have a Dublin citybreak at each side of the trip, more than paid for by the fare difference. Seems bonkers this is even possible.