- Eurostar trains run from central London; cheap flights leave from Luton, Stansted, and Gatwick, none of which are close to London, and which therefore all potentially require a time-consuming extra transfer, at some additional cost.
- if you have flexibility on time and book a little in advance, one-way Eurostar tickets for one adult can be found for ~£50, and easily for less than £100.
So it’s more like ~£107 versus ~£200-400, if you live near a relevant airport, or in central London, respectively.
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Of course, this still doesn’t explain why running a train should be several times more expensive than a plane. I’m not sure the absence of environmental taxes (as argued in the article) is the full explanation- this sounds more like a mechanism to force price parity, rather than the root cause?