Families are around £34 a month worse off than they were a year ago, as the squeeze on people's budgets continues, a study has found.
High inflation, which has pushed up the cost of essentials, has been easing, but weak income growth will "severely limit" any benefits to be felt by consumers until the economy grows more strongly, the Lloyds TSB Spending Power report found.
A 0.3% decline in spending power after inflation meant that households had around £34 less to spend on non-essential items in May compared with the same month in 2011.
Eight out of 10 people surveyed believe the rate of inflation is not good, despite growth in spending on essentials falling back to 3.9%, from 4.6% in April.
Annual growth in spending on vehicle fuel slowed to 5.1%, the lowest rate since the index began in January 2010, while debt payments and water bills also saw notable declines in annual growth.
Lloyds TSB chief economist Patrick Foley said: "Weak income growth and stubbornly high inflation is ensuring the consumer squeeze is remaining longer than many thought it would.
"Growth in spending on essentials is now showing signs of moderating which is positive. But the weakness in income growth is severely limiting the benefits.
"I would expect the benefits of falling inflation on consumers' spending power will be limited until we also see a stronger economy and faster income growth."
Household finances showed some general improvement in May, with 54% of people surveyed saying that they live comfortably or meet their outgoings with some left over each month, a rise of six percentage points since April.
The report, which surveyed more than 2,000 people, defines spending power as income left over after spending on essentials such as rent and mortgage payments and other regular bills.
The monthly decline in spending power that has hit households in the UK