Introduction

This report analyses income inequality trends in the UK using data from the World Inequality Database (WID).
We examine long-term changes in the share of income held by the top 10% and compare them with the USA and France.

Methods

Data was sourced from the World Inequality Database (WID), containing annual measures of income share by percentiles for multiple countries.
For this report: - We selected the variable P90–P100 – share of the top 10% as the main indicator of inequality.
- Data was filtered for the United Kingdom, the United States, and France.
- Summary statistics were calculated for the UK (minimum, maximum, average share, first and last years in dataset).
- Time-series line plots were created using ggplot2 in R to show historical trends.
- All values are expressed as a percentage of pretax national income.

UK Top 10% Income Share

The UK shows a clear U-shaped trend: high inequality early in the 20th century, a decline mid-century, and a rise since the 1980s.

Summary Statistics for UK

## # A tibble: 1 × 5
##   First_Year Last_Year Min_Share Max_Share Average_Share
##        <dbl>     <dbl>     <dbl>     <dbl>         <dbl>
## 1       1908      2017      28.2      38.7          32.6

This table summarises the range and average of the top 10% income share in the UK over the available data period.

UK vs USA vs France

The comparison shows that while all three countries have seen increases since the 1980s, the USA’s rise has been more pronounced, and France’s increase more modest.

Conclusion

The analysis highlights a U-shaped trend in UK income inequality over the last century, with the lowest levels in the mid-20th century and a steep rise since the 1980s.
International comparison reveals that the UK’s pattern is closer to the USA than France, though the USA’s inequality has grown faster and to a higher level.
These patterns likely reflect differences in tax policy, welfare systems, and labour markets.
Understanding these long-term trends can guide future policy to address inequality. ```