The claim that Brexit would redirect 350m/week to the NHS was a particularly egregious example.
[0] https://www.bma.org.uk/advice-and-support/nhs-delivery-and-w...
There’s many ways to calculate what that expenditure should be but looking at the most recent pre Brexit numbers, 2018 was 150.7B, 2019 was 158.3B. Extrapolate that trend and 2023 would be 7.6 * 4 + 158.3B ~= 188.7, where the real number is projected at 186.7B.
PS: That link only specifies 2020 and 2021 as seeing COVID specific spending but the UK health system was still being slammed in 2022 while also trying to catch up on delayed procedures etc. https://www.worldometers.info/coronavirus/country/uk/
NHS Funding Act 2020