Lower-income households are using savings and borrowing more during the coronavirus lockdown, while richer families are saving more as eating out and trips abroad are banned.
That's according to research from the Resolution Foundation, a think tank.
Lower-income households are twice as likely as richer ones to have increased their debts during the crisis, it said.
Workers in shut down parts of the economy have average savings of £1,900, it found.
That compares to the £4,700 buffer of someone who has been able to work from home during the lockdown.
"Pre-coronavirus Britain was marked by soaring wealth and damaging wealth gaps between households," said George Bangham, economist at the Resolution Foundation.
"These wealth divides have been exposed by the crisis. While higher-income households have built up their savings, many lower-income households have run theirs down and had to turn to high-interest credit."
According to the research, which was funded by the Standard Life Foundation charity, wealth gaps across the country have also grown.
The study found that London and the South East accounted for 38% of all wealth between 2016 to 2018, up from 32% a decade earlier.
Wealth inequality remains almost twice as high as income inequality, it adds.
Impact on young people
Last month, the think tank found that young people are most likely to have lost work or seen their income drop because of Covid-19.
More than one in three 18 to 24-year-olds is earning less than before the outbreak, it found.
It said younger workers risk their pay being affected for years, while older staff may end up involuntarily retired.
Last year, a different think tank, the Institute for Fiscal Studies, found widening inequalities in pay, health and opportunities in the UK are undermining trust in democracy.
It warned of runaway incomes for high earners but rises in "deaths of despair", such as from addiction and suicide, among the poorest.