More than 20 million meals were given out to people at risk of going hungry in Britain last year, with the Government's welfare reforms "a driver of food poverty", a report by major charities has found.

The principle of a social security system safety net appears to be under threat, the report said, with welfare cuts having a "severe impact on poor and vulnerable families".

The report, by Oxfam, Church Action on Poverty and the Trussell Trust, called on the Government to urgently investigate the issue and produce an action plan to tackle the "stain on our national conscience".

Analysis by Oxfam and Church Action on Poverty found that 20,247,042 meals were given to people in food poverty in 2013/14 by the three main food aid providers - the Trussell Trust, Fareshare and Food Cycle - an increase of 54 per cent on the previous year.

Food banks are now working in many Wiltshire towns including Devizes, Chippenham and Trowbridge.

"Protecting its citizens from going hungry is one of the most fundamental duties of government," the Below the Breadline report said.

"Most of us have grown up with the assumption that when we fall on hard times, the social security safety net will kick in and prevent us from falling into destitution and hunger.

"The principle of this crucial safety net now appears to be under threat."

The report said cuts to social security since April 2013 have had a "severe impact on poor and vulnerable families across the UK" and they were combined with "an increasingly strict and often misapplied sanctions regime".

While food banks were a "vital lifeline to those in need" they are a "sign of fundamental failure and they should not become an ever-growing feature of life in 21st century Britain".

The report said: "The Government must first commit to really understanding and monitoring the true scale of this problem, then set out ambitious steps to tackle it.

"This will require a willingness to accept where mistakes in policy and practice are being made, and put in place measures to repair the social safety net. It will also mean taking steps to ensure that people have decent, secure jobs so that they can earn their way out of poverty and to tackle the rising cost of living.

"This will mean visionary policy making; but if these issues are not addressed, many people are going to continue to struggle, living below the breadline."

UK food prices have increased by 43.5 per cent in the eight years to July 2013 and while more affluent consumer could switch to cheaper brands to save money the poorest shoppers, who were already buying the lowest-cost foods, had no choice but to eat less.

Some were living on one meal a day, drinking hot water and lemon to tame hunger pangs, the report said, with more than half a million children in the UK now living in families who are unable to provide a minimally acceptable diet.

Oxfam chief executive Mark Goldring said: "Food banks provide invaluable support for families on the breadline but the fact they are needed in 21st century Britain is a stain on our national conscience. Why is the Government not looking into this?

"We truly are living through a tale of two Britains; while those at the top of the tree may be benefiting from the green shoots of economic recovery, life on the ground for the poorest is getting tougher.

"At a time when politicians tell us that the economy is recovering, poor people are struggling to cope with a perfect storm of stagnating wages, insecure work and rising food and fuel prices.

"The Government needs to do more to ensure that the poorest and most vulnerable aren't left behind by the economic recovery."

Niall Cooper, director of Church Action on Poverty, said: "We want all political parties to commit to re-instating the safety net principle as a core purpose of the social security system, and draw up proposals to ensure that no one in the UK should go hungry."

The Trussell Trust's chairman Chris Mould said the problem was a "national disgrace" and added: "Unless there is determined policy action to ensure that the benefits of national economic recovery reach people on low-incomes we won't see life get better for the poorest any time soon."

A Government spokesman said: "It's simply not possible to draw conclusions from these unverified figures drawn from disparate sources. They cover a wide variety of provision including food redistributed to places such as community cafes, lunch clubs for the elderly and children's breakfast clubs which are frequented by all sorts of people.

"This report also overlooks basic facts about the strength of our welfare system. We provide a vital safety net, spending £94bn a year on working age benefits to support millions of people who are on low incomes or unemployed.

"As part of our long-term economic plan we're fixing the welfare system to improve the lives of some of the poorest families in our communities by promoting work and helping people to lift themselves out of poverty.

"We've also helped families by cutting the cost of living, more people are in work helping to support their family, benefits are being paid to claimants more quickly and according to independent experts fewer people report struggling with their food bills compared with a few years ago."