nd time value adjustment Time value adjustment to 2023 value Cost and benefits were adjusted to 2023 value using the Green Book social time preference rate (STPR) of 3.5%, on the basis of which we calculated a time value coefficient for each year, calculated as follows for any given year n in the past: (1+3.5%)^n. Years 2015 2016 2017 2018 2019 2020 2021 2022 2023 (STPR) 3.50% 3.50% 3.50% 3.50% 3.50% 3.50% 3.50% 3.50% 3.50% Time coefficient to 2023 1.32 1.27 1.23 1.19 1.15 1.11 1.07 1.04 1.00 Inflation adjustments to 2023 value Costs and benefits were adjusted to 2023 values using a GDP deflator. The source of the deflator is from the latest Gov UK GDP deflators at market prices and money GDP in March 2024, available at https://www.gov.uk/government/collections/gdp-deflators-at-market-prices-and-money-gdp . We calculated a GDP coefficient adjustment for each year, denoted as 'n', as: (price index for year 2023) / (price index for year 'n'). Years 2015 2016 2017 2018 2019 2020 2021 2022 2023 Index 2023 = 100 78.21 79.74 81.22 82.78 84.53 89.02 88.73 93.29 100.00 GDP Inflation coefficient to 2023 value 1.28 1.25 1.23 1.21 1.18 1.12 1.13 1.07 1.00 9e. Total cost calculation Years 2015 2016 2017 2018 2019 2020 2021* 2022 2023 Total Total initial development £180,759 £0 £39,284 £20,074 £0 £26,326 £72,028 £8,470 £0 £346,941 Total maintenance £24,135 £24,135 £24,135 £24,135 £24,135 £24,135 £34,390 £34,390 £34,390 £247,979 Total ongoing development £48,405 £48,405 £48,405 £48,405 £53,405 £48,405 £63,660 £58,660 £63,660 £481,406 Total cost £253,298 £72,539 £111,823 £92,613 £77,539 £98,865 £170,077 £101,519 £98,049 £1,076,326 Time coefficient 1.32 1.27 1.23 1.19 1.15 1.11 1.07 1.04 1.00 GDP inflation coefficient to 2023 value 1.28 1.25 1.23 1.21 1.18 1.12 1.13 1.07 1.00 Total cos