I few years ago I was the lead technical resource for an in house consultancy at RELEX and solved major problems for house hold names and I got paid < 1/2 what a train driver does for a 4 day week.
You both need to realize you are lucky and also learn some maths you colleague who earn 50% less than you is not coming out ahead.
A household with one earner on £50k has a post-tax income of £37k, 26% above average as a household, and lightly under average for the size of household.
My collegue who earns 50% less for 50% of the work does come out ahead. My household works 40 hours a week and gets £50k, her household works 40 hours a week and gets £50k. Our marginal tax rate is over 60%, theirs is 33%.
https://www.telegraph.co.uk/business/2016/08/17/britons-bett...
If you look at households with two adults and two children, this kicks in just below the median [2]
The upshot is that I do £1k overtime, which costs my employer £1138, and I keep £400 My collegue who earns 50% as much as me keeps £600 My contractor collegue who is paid twice as much gets paid that £1138 and he keeps £682 My part time collegue who does 5 days a fortnight and gets paid more per day than I do keeps £670 (as does her husband who does the same shift pattern - so they have the same pre-tax household income but far more post-tax)
Not exactly progressive.
[0] https://www.virgintrainscareers.co.uk/VacancyInformation.asp... [1] https://www.telegraph.co.uk/news/2016/03/15/how-well-off-are... [2] https://www.theguardian.com/money/2014/mar/25/uk-incomes-how...