The Equality Trust says figures from the Office for National Statistics, which reveal a gap of nearly £25,000 between the UK's highest and lowest earners, "paint a depressing picture of dangerous income inequality".
In Telford and Wrekin, the average weekly pay packet for the top 20 per cent of earners in full-time roles is now 2.1 times those in the bottom fifth – a gap of £20,535.
In Shropshire it is 2.2 times those in the bottom fifth – a gap of £22,266, and in Powys the gap is £18,502.
The figures, for workers who live in the area, use median, rather than mean, averages, to stop them being skewed by particularly small or large salaries.
In Telford they show the top 20 per cent of earners were paid £754 weekly on average, or £39,208 annually.
For low earners, weekly pay was just £359 – £18,673 a year.
The average full-time employee in Telford and Wrekin works 37.5 hours per week, with a median annual salary of £25,969.
For Shropshire the top 20 per cent of earners were paid £798 weekly on average, or £41,475 annually.
The figure for low earners, weekly pay was just £369 – £19,209 a year.
It means that the average full-time employee in Shropshire works 37.5 hours per week, with a median annual salary of £27,612.
The figures refer to basic pay and do not include bonuses or overtime.
Across the UK, the average annual salary for the top 20 per cent of earners is 2.2 times as high than the lowest earners.
Top earners are paid £44,533 on average, compared to £19,874 for their lowest-paid counterparts.
London had the greatest gap, where top-paid earners took home £56,300 – nearly £33,000 more than low earners.
Most equal was Wales, where the highest 20 per cent of earners were paid 2.1 times that of the lowest fifth.
Dr Wanda Wyporska, executive director of charity the Equality Trust, said: "Just like the gender pay gap, the gap between high and low paid workers is not shrinking fast enough.
"But this is an even greater scandal because the evidence shows that in countries with high levels of inequality, like the UK, there are higher levels of violent crime, physical and mental ill-health, infant mortality and lower levels of trust and educational attainment.
"By continuing to ignore inequality, decision makers are failing to truly realise the social and economic potential of this country."
The Trades Union Congress estimates one in nine UK workers are in insecure and poorly paid "precarious work", including those on zero-hours contracts and self-employed people making less than the minimum wage.
General secretary Frances O'Grady said: "Working people deserve a fairer share of the wealth they create. It's not right that millions are struggling to make ends meet, while those at the top pocket bumper pay cheques.
"We need to reset the balance of power in our economy.
"That means giving workers new rights so they can access the protection of a union in every workplace and bargain for better pay and conditions across industries."