The data may still be sketchy and the evidence largely anecdotal, but there are signs that shoplifting food is becoming an austerity-era shoplifting phenomenon: more people stealing to eat because they cannot afford basic groceries.

Teenage asylum seeker Amine Ahnini was almost destitute when he stole a sandwich from Sainsbury's last year. Ahnini, who is not allowed to work, had £35 a week for food, clothes and travel, and said he would often go for one or two days without eating.

But it is not just asylum seekers driven to desperation thefts. Charities and police say that as living costs rise and incomes shrink, "stealing to eat" is increasing and the shoplifter demographic is widening. Officers say food shoplifters can be mothers struggling to feed their children, or hungry pensioners. In many cases they have no criminal record. The rise is more marked in deprived areas.

For instance, cases logged by South Yorkshire police include four instances of grocery shoplifting by mothers in 2012. Among them were a 31-year-old who stole baby milk and fabric conditioner worth £17.50, and a 19-year old who took baby milk and clothes worth £70. All told police they had shoplifted to feed and clothe their children. Three of the four had no previous convictions. All were given a fixed penalty notice.

South Yorkshire chief superintendentJason Harwin said: "There should be no excuse for committing a criminal offence. These examples, however highlight the desperation some individuals face, that they are turning to crime to support their family."

Last year Greater Manchester police said while shoplifting offences in its patch overall were decreasing – the British Retail Consortium's 2011 Retail Crime Survey found shoplifting in the UK at its lowest level in seven years – the proportion involving groceries was rising.

Ch Supt Chris Sykes told a conference: "It's our feeling that a significant proportion of that is people stealing for themselves rather than stealing to sell on a big joint of beef, for example. In the past, you had stealing to order but now people are stealing for their own use."

In Glasgow officers reported a similar increase in "stealing to eat" crimes. "We had an old man who had taken three tins of salmon. He could not afford to feed himself," Ch Insp Ann Hughes said last year.

Forces across the country are referring some shoplifters to food banks. In south London, a Metropolitan police safer neighbourhoods team said it had given out 75 vouchers for the Norwood and Brixton food banks since the partnership began six months ago. An officer said: "I've brought some young people into custody and realised they haven't eaten for 36 hours or so. You give them food bank vouchers, which they can use at the local church."

Adrian Curtis, the network director of the food bank charity Trussell Trust, said he regularly heard stories about desperately hungry people stealing food. "They were not stealing high-priced items, but food to feed their family," he said.

In a survey of 45 food parcel recipients by Coventry food bank, which feeds more than 210 people every week, just under half answered yes to the question "Have you ever needed to steal to feed you or your family?" Shane Feeney, who gathered the data, said: "Some people said they regretted having to steal but didn't have any other option; others felt embarrassed about the question. The number might be higher than recorded as people may have thought they might get in trouble if they answered yes."