You asked
The requester would like to know the population of London and the UK.
We said
The population of the United Kingdom at 30 June 2015 (the most recent year of data available) is estimated to be 65,110,000. The population of London at 30 June 2015 (the most recent year of data available) is estimated to be 8,674,000.
These figures and tools to explore the data can be found on the ONS website at https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/populationestimates/bulletins/annualmidyearpopulationestimates/mid2015