The fact that feeding the hungry and destitute is the fastest growing part of Scotland's voluntary sector gives the lie to Coalition claims about fairness.

For, as Olivier de Schutter, UN rapporteur on the right to food, puts it: "Access to food is the perfect bellwether for broader social inequalities."

In 2004 the Trussell Trust, a Christian charity, operated just one UK food bank. Today there are more than 300. In Scotland there are 15, with another 15 opening soon. The numbers receiving emergency food from the charity have increased from less than 6000 to more than 14,000 in a single year. And, though it is the best known, the trust is only part of a much wider network of charitable help given on an informal basis by church and voluntary groups to the growing numbers who find themselves unable to afford to buy food.

Clearly this situation is politically embarrassing for the Westminster Government. It does not suit their narrative, with its vocabulary of "skivers and strivers", especially when so many of those using food banks are low-paid workers facing cuts in their top-up benefits. They have been called "the purest form of the Big Society" but it is unlikely that David Cameron had food banks in mind when he floated the concept three years ago.

Since then they have become a privately funded safety net that is required to compensate for the state's torn safety net of what used to be called "social security".

It is telling that 29% of the Trussell Trust's Scottish clients have been caught short by delays in their benefits and another 15% have been hit by benefit changes. There is worse to come as changes such as the bedroom tax kick in and as prices continue to rise faster than pay and benefits.

Charities such as the Trussell Trust play a vital role in crisis management. The risk is that they become a de facto substitute for state help, replacing rights and entitlements by charity. Soup kitchens that sprung up in the 1980s in the US to deal with what was seen then as a short-term need have ended up becoming a permanent feature as the welfare system shrivels. In the UK already some councils are offering funding to their local food banks. It is important that they are not allowed to morph into a branch of the welfare state and that, while condemning the conditions that have made them necessary, politicians and commentators do not stigmatise those who have the misfortune to rely on them.

In a labour market where many of the poorest are constantly moving in and out of low-paid insecure employment, more needs to be done to get state help where and when it is needed. There are doubts that Universal Credit will live up to its billing on this. It must not be rolled out until it can be shown to work. More generally, in a country where millions enjoy the luxury of hyperconsumption, state benefits and the minimum wage should be set at levels that enable everyone to put food on their table. It is wrong that in what remains one of the richest countries in the world so many people have to rely for their basic needs on the kindness of strangers.