Saturday at my local Tesco. For three days Tesco teamed up with the Trussell Trust to allow people from local TT food banks to stand at the front of the store and ask shoppers to donate items for the local community from a small list.

Tesco was doing its bit. A huge selection of its value basics range was on show so shoppers could instantly grab items ranging from value orange juice to value cereal and put it in with their shopping.

After passing the checkout you would then put the items into the donation-marked trollies. Customer service staff then wheeled them away to the storage area and then apparently Tesco would match whatever was donated with 30 per cent more.

Sounds fine in theory. But as I stood talking to the food bank volunteers, watching our MP turn up to promote the event and then watching shoppers scurrying past, I felt uncomfortable on many fronts.

The Tesco brochures and the tabards each volunteer wore did not mention the word "food bank," only the following. "Together we can help feed people in need and build a stronger neighbourhood."

On the tabards were tiny mentions of Fareshare and the Trussell Trust. TT is the organisation behind the setting up of food banks across Britain. I felt annoyed that the term food bank had been omitted from Tesco's literature. I asked a Tesco employee about it.

"The food donated is going to the local food bank" - I will dispute this fact later - "but perhaps the term was too emotive for management to use. The words community and neighbourhood were probably felt to be more appealing to those people who wish to donate."

My view is a more cynical one, born out of three years of the coalition government.

Food bank use has soared relentlessly since 2010. Using the term food bank was probably seen by Tesco as too political, yet in reality the food donated was indeed going to one.

The volunteers on the day I was there were all elderly, genteel folk who were asking everyone who came through the doors very politely whether they would like to donate.

I asked where the food was going to.

"To the local food bank," the TT co-ordinator said.

"Are you certain?" I asked.

"The local food bank that serves this town and Rhyl down the road is independent and not run by the TT. Will they benefit from three days of donations?"

"Well, no ... um ... we are from a food bank in the same county, but as the local food bank is not TT or part of the Fareshare scheme they will not benefit from the collection at all, sorry."

The food bank that was collecting was actually 15 miles away from the local community and neighbourhood of my own town and the Tesco supermarket.

The local community of people in need therefore would not benefit at all by the food donations. I told both Tesco and the TT volunteers I was unhappy that they were not pointing this out to local people.

Personally I am not bothered that my donation was feeding a family 15 miles away, but I thought that people donating foodstuffs should receive the full facts.

My local food bank told me the reason it remains independent is to have control over the amount of help they give people.

Ours, for example, does not have set rules on the amount of times a parcel can be given. They receive referrals on the basis of need and much of that need is ongoing.

Back in Tesco, things were not going well. The elderly volunteers were trying hard to get people to donate but in a very subtle way. Obviously they had a remit that they could not hassle people. A few shoppers walked past, heads bowed to avoid being asked, but some openly said: "I'm not donating to scroungers" or "People should get a job" and then walked off.

Being younger I challenged a few people. "Do you know 80,000 children will wake up homeless and in a B&B on Christmas Day?

"Do you realise under this government half a million people will need help from food banks this year compared to 24,000 in 2008?

"Think how you would feel if you had an accident, a divorce or an illness and were forced to claim a state benefit.

"Imagine that benefit takes six weeks to come through and you have nothing. That's where a food bank comes in!"

I got very angry and worked up. Not by the people who stopped and said: "Sorry, but I literally have no spare cash myself for shopping."

I actually admired their honesty. It was the well-heeled people who walked on by that upset me most.

At times I felt almost Bob Geldof-ish and wanted to shout: "Give me your fucking tins!" But I couldn't in the confines of the shop.

I turned my attention to the mountains of value everyday basics food on promotion for those who wished to donate - a pile of white tins, packets, jars that screamed: "This food is only fit for the poor."

Lying in the donated food trollies the anaemic-looking tins angered me more. I asked the customer service adviser why Tesco thought their value range only was suitable for donation and on promotion.

"Shoppers may not have a lot of money themselves. We are showing them that a tin of beans, a carton of value juice can be donated with little cost and people needing food banks are desperate anyway..."

Hardly able to contain myself I went around the shop, I came across the tinned fruit aisle.

One tin of value orange segments was 32p, yet at 43p Tesco-branded orange segments were on a buy-one get-one-free, so for 11p more two tins could be donated and they would be of better quality too.

A 1kg family box of Kellogg's cornflakes was on offer at £2 yet the value box at a third of the size was 86p and worse-tasting. After having paid I brought my donated goods to the volunteers.

"How kind," one said.

"Not kind at all," I said. "There are special offers in this store that donors could be pointed to. My kids like Kellogg's cereal, so why shouldn't a child whose parents receive a food bank parcel enjoy the same quality?

"Come to think of it, why aren't Christmas type items like small selection boxes, shampoo, shower gel, on this list?

"Even toys for children? Baby food, baby milk, nappies, sanitary towels, soap, toothpaste ... do people at food banks not need these things too? Even pet food. Pets still have to be fed or they end up at the RSPCA."

"We have to stick to the list given, but people are welcome to donate such items if they wish," the volunteer said.

But nobody was telling them this information. Tesco was making a fortune out of the promoted value basics range sale over three days but was only matching it by 30 per cent.

Whatever happened to the Christmas spirit? A 100 per cent matched donation would not make a dent in its profits.

Why was there no-one either from TT or Tesco educating people about the huge rise in food banks?

As I put the goods into the food bank trolley I could almost hear David Cameron laughing at me. You see, you and I are the "big society" in action.

We are feeding people Cameron's government has turned its backs on. Yet my feeling of guilt and those of other donors are what is being relied upon. Local communities will not let local people starve and that is the bottom line.

If you are donating to a local food bank this Christmas, ask questions. Even ask to volunteer.

A lot of volunteers are retired who would most likely welcome younger people to help those in desperate need of food.

This year we are aghast that foodbank use has risen to 500,000 people.

Will we be disgusted or simply shrug when that figure reaches a million in years to come?

Bernadette Horton blogs at mumvausterity.blogspot.co.uk