Fares move with demand and season, so your date matters — the cost figures below are typical indicative ranges, not a live quote. Carbon is calculated from fixed UK Government emission factors and doesn't change with price.
Carbon per person
80% less
by sleeper vs flying — about 5× lower.
Hotel night saved
~£110
The sleeper is your bed for the night — so you skip one hotel booking and arrive at breakfast.
Fly during the day and you either lose a working day or pay for a night's accommodation. The train gives you both the journey and the night.
All-in cost, one way
£170–£240
sleeper cabin (travel + bed)
Flight side includes a typical £110 hotel night and airport transfers the sleeper doesn't need.
How we work it out
Carbon uses the UK Government's 2024 greenhouse-gas conversion factors: 35.46 g CO₂e per passenger-km for national rail and ≈246 g CO₂e per passenger-km for an average domestic flight (the flight figure already reflects the fuel-heavy take-off and landing on short hops). We multiply each by the route distance — published rail route distance for the train, great-circle distance to the nearest airport for the flight. Cost figures are indicative one-way ranges: the sleeper cabin is travel plus a bed, while the flight side adds a typical £110 hotel night and airport transfers, because a daytime flight still needs somewhere to sleep. Always check live fares for your date.
Sources: UK Government GHG conversion factors 2024, Our World in Data — travel carbon footprint, Seat61 — CO₂ of trains vs planes.