Residents in Wiltshire have just over a third of the disposable income of people in some other parts of the UK.
The average person in Wiltshire had £22,522 left after tax in 2018, the most recent Office for National Statistics data shows.
By contrast, people in Kensington and Chelsea, and Hammersmith and Fulham had more than double as much – left with £63,286 each.
Wiltshire's average disposable household income increased by 6 per cent – more than the UK average of £21,209.
The lowest disposable income in the UK – £13,138 – was in Nottingham.
Dr Wanda Wyporska, executive director at the Equality Trust, said: "The figures are a damning indictment of the glaring inequalities between London and the rest of the country and between north and south, rich and poor.
"This is even more important, as part of the background to the current Covid-19 crisis, which we know has seen higher rates of death in more deprived areas.
"We know that high levels of inequality are accompanied by higher levels of poor mental and physical health, drug and alcohol addiction, violent crime and imprisonment and lower levels of social mobility and educational attainment."
The UK's total gross disposable household income increased by 5 per cent in 2018, to £1,402 billion.
Every region saw an increase in GDHI per head in 2018, but London's remained the highest, at £29,362 on average.
By contrast, the South West's was just £20,907 – the fourth highest.
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