Household finances are under greater strain now than at the height of the recession in 2009, new figures issued today reveal, raising further concerns over the recovery of the British economy.

High inflation, high unemployment, rising debt levels and falling take-home pay have led to the fastest drop in household savings and available cash since monthly figures were first collected two and a half years ago.

Markit's Household Finance Index for August hit a new low of 33.2 (readings below 50 signal a deterioration in finances, above 50 an improvement), with two out of five households reporting deteriorating finances over the month compared with just one in 20 recording an improvement.

Tim Moore, a senior economist at Markit, said: "Recent events have made a week seem a long time in economics, and August's survey is the first sign that the slew of downbeat headlines has knocked consumer sentiment. Households reported the sharpest deterioration in their finances since the survey began, exceeding even that seen during the worst point of the recession."

The survey began in February 2009 but August's fall – for the third month in succession – suggests that household finances are deteriorating even faster than when the recession was in full sway. With key costs including energy and public transport set to increase, the future is looking bleaker than ever for families.

Some nine million homes were hit last week when the latest price increase from British Gas came into force. Increases of 18 per cent on gas and 16 per cent on electricity have pushed up the average dual fuel bill by £190 a year to £1,219, meaning the average household now has a monthly energy outlay of more than £100 for the first time.

Last week's inflation news that the retail price index was unchanged at5 per cent is also bad news for anyone using rail travel.

There was further bad news in the Markit survey, including the fact that there has been the fastest fall in cash available to spend since the research began. There has also been the largest rise in debt levels for nine months, as total debt increased for the fifth month running.

Tony Dolphin, the chief economist for the Institute for Public Policy Research, warned that the strain could undermine Britain's economic recovery.

He said: "Household finances are under strain, with inflation rising faster than wages, the recent rise in VAT and rises in home energy bills. Rising unemployment is also causing anxiety and insecurity. With people tightening their belts it means they have less to spend and a lack of consumer confidence will undermine the fragile recovery."

Mr Moore warned that the squeeze on consumer purchasing power was unlikely to abate in the near term.

The Bank of England's preferred measure of inflation – the consumer price index – climbed from 4.2 per cent in June to 4.4 per cent in July and is expected to reach 5 per cent later this year as higher utility and oil-related prices filter through to household budgets.

"With consumer spending accounting for around two-thirds of UK gross domestic product, this does not bode well for the economy in the second half of the year," Mr Moore warned.

"The overall findings of the survey suggest little in the way of a springboard for consumption growth in the year ahead. As a result, it is likely that the UK economy will be increasingly dependent on external demand to drive the recovery."

Kerry McCarthy, Labour's Shadow Treasury Minister, said the new figures "show how tough things are for families up and down the country".

"If families are cutting back spending, the recovery risks being choked off," she said. "We need a balanced plan that puts jobs and growth first – more people in work paying taxes and fewer out of work on benefits is the best way to get the deficit down."