I don't know if that's the case here, but costs for large, long-term projects are often quoted by year of expenditure. Costs to be incurred more than a few year

I don't know if that's the case here, but costs for large, long-term projects are often quoted by year of expenditure. Costs to be incurred more than a few years out are adjusted for expected inflation, with total costs the sum of all these inflation-adjusted numbers. This is how public works capital projects are typically quoted in the United States, and it's one reason budgets grow so quickly, especially if timelines keep getting stretched out into the future--e.g. California High-speed Rail. EDIT: The report's figures are discounted. From the report[1], page 8: "Many of the larger items described represent spending commitments spanning years into the future (in some cases, beyond 100 years). In accordance with accounting rules, these items are adjusted to reflect the time value of money, where expected future payments are discounted to provide a present value. " [1] https://www.ukgi.org.uk/download/5767/?tmstv=1701723390 https://www.ukgi.org.uk/download/5767/?tmstv=1701723390 via https://www.ukgi.org.uk/2023/11/22/clccs-annual-report-on-the-uk-governments-contingent-liabilities/ https://www.ukgi.org.uk/2023/11/22/clccs-annual-report-on-th...