John Glen is MP for Salisbury and South Wiltshire.

Earlier this week, the Trussell Trust released its annual figures showing its food banks had handed out 913,000 parcels of emergency food – up from 347,000 last year.

I am proud to represent the Trussell Trust, which was founded in Salisbury: it does an enormous amount of good across the nation and meets an emergency need for many vulnerable people. I look forward to working with it on a joint paper for the All Party Parliamentary Group on Hunger and Food Poverty about how one food bank that started in a garden shed has now become the dominant franchise model for communities across the country.

The figures from the Trussell Trust make interesting reading, but it is important to look beyond the media’s headlines and dig deeper into them. The Trussell Trust’s data is some of the most robust of its type: but, as with all statistics, it has its limitations.

First, their analysis of six of their own food banks (including Salisbury) shows that 65 per cent of people only visited once. Just 7.5 per cent of those who used these foodbanks needed four or more vouchers. Although this was a small scale study, it does highlight that the national dataset does not distinguish between people who visit once and people who visit multiple times – it was not designed to do so – and therefore we should be cautious about deducing that “a million people” have visited in the last year.

Second, the biggest reason for referral, according to the Trust’s data, remains benefit payment delays, which accounted for 31 per cent of referrals this year. The DWP has made progress in this area, notably a six per cent improvement on the number of payments made on time since 2009, but of course there is more work to do. The DWP rightly emphasises the importance of ensuring a full and effective roll out of universal credit in addressing the existing cumbersome system.

However, this also raises a point about the wider debate on food bank use. We need to start asking what combination of circumstances converge in an individual’s life before they reach a crisis point and approach a professional asking for a food bank referral voucher. This means not isolating one cause because it is politically expedient to do so, or relying on a collation of tickbox responses to define a much more complex set of circumstances.

Too often, the discussion has drifted towards two polarised political arguments. There are some who allege that the full responsibility for a visit to a foodbank lies purely with the individual. To these commentators, the benefits system is adequate, providing the money is used as intended, and a visit to the food bank is a reflection that “poor choices” have been made and money has not been spent wisely.

Then there are those who argue that the current Government should bear full responsibility, and that cruel and savage welfare cuts and an “aggressive” sanctioning regime are entirely to blame. These commentators argue that welfare reform is a misguided agenda that is being poorly delivered.

I believe the reality is that every case is different and that sweeping generalisations about causes do not do justice to the complexity of individual family circumstances. I do not agree that “poor choices” are at the root of every case but, on the other hand, I do not think we can ascribe welfare reform as the primary cause either.  As Frank Field, the respected former Labour Minister, argued at the launch of the APPG’s inquiry earlier this month: “even if we abolished all the welfare reforms that the Government had done, we would not abolish the need for foodbanks”.

In the heavily polarised debate that we have now, the cause always seems to be either “poor choices” or “benefit cuts” – and a discussion about other factors is squeezed out as a result. For instance, there is seldom discussion about how the cost of housing has risen for all generations; or how the employment market has become more flexible, and people often move in and out of different jobs at short notice; or how the cost of utilities and food have risen as a proportion of total household spending, and the amount that households are saving has steadily dropped as a result.

Families have seen their finances come under pressure due to this combination of long term factors and are therefore left in a more vulnerable place. As a result, when disaster strikes for these households – if the boiler breaks down, or the washing machine needs fixing, or hours at work are reduced at short notice – it can prove a blow to the family budget and quickly leads to a crisis.

It seems to me that, more often than not, it is not one specific factor that causes the trip to the food bank, but the cumulative impact of many long term issues mounting up. Unfortunately, there is no method to categorise the problem neatly, or to weight the different causes on a tickbox sheet, and therefore the data we have currently can only show the one most recent factor driving the food bank visit.

Unless we look at the complex reasons leading up to a family or individual presenting at the food bank, with a thorough and dispassionate look at these longer term causes in particular, we will not be able to move on from the sometimes unhelpfully rhetorical debate we currently live with.

As politicians, we have a duty to ask what happened leading up to the moment of crisis so we can target resources towards education, intervention and prevention in the future. I hope that the work of the APPG’s hearings and inquiry will lead us to move away from the unedifying headlines. I enter into it with an open mind, and hope that what we hear from food banks and churches across the country will provide a greater evidence base and a more informed national debate.

It is worth remembering that foodbanks have grown across the western world and across the tenures of Governments of all political persuasions – Britain is not alone in this respect. However, politicians across the political spectrum will be better able to comment authoritatively if they have a greater body of detailed evidence on which to base their assessments.