STEVE CANAVAN: Being overcharged for posh prawns really raised my tempura

It was clearly stuff that had been left over from Christmas '“ sausage rolls, spring rolls, prawns in something called tempura batter, which looked like normal batter but adding the word 'tempura' presumably gives it an air of mystery and makes the massive price tag easier to justify '“ but it was quite a good deal from a fiver down to £2.50.

I didn't need any of this food '“ I don't even like prawns, they give me terrible wind '“ but it seemed a bargain and I figured that on the off-chance we were to host a party in the foreseeable future, it was the kind of thing we could shove on a plate in the lounge for guests to nibble on.

'I say Steve, that batter tastes beautiful.' 

'Yes Dave, it's tempura. Lovely, isn't it?'

After adding a few more items to my basket '“ bread, yoghurt, Mrs Canavan's upper lip hair removal cream '“ I headed to the till where I was served by a woman who I think last smiled around the time of the Falklands War.

The term 'businesslike' doesn't do her justice. She treated me less like a customer and more like a contagious infection.

Anyway, I paid my bill and although I do remember thinking, '˜that was a tad more expensive than expected', I was in the kind of trance that comes after a long, joyless day at work and went back to my car and drove home.

It was only on unpacking my goods and glancing at the receipt in the act of hurling it into the bin that I noticed they had charged me full price for the half-price food.

Now this was intensely annoying as had the grub been full-price, I wouldn't even have glanced at it. I mean, do I look the type of guy to spend £5 on tempura prawns? I balk at spending £5 on a new pair of trousers.

'˜What are you muttering at?' asked Mrs Canavan.

I told her. '˜You should have checked before you left the shop, you idiot,' she said sympathetically.

I put the receipt on the mantelpiece, thinking I'd bob back to store on my way home from work the following evening.

But as I sat in the lounge watching Greg Wallace gurn his way through an incredibly dull documentary about mayonnaise '“ did you see it? I have never witnessed one man get so animated about a machine that separates egg yolks from the whites '“ I simply couldn't rest.

The whole injustice of it was playing on my mind. Within three minutes, I could stand it no more and announced to Mrs Canavan I was heading back to M&S.

Not for the first time, she looked at me as if wondering why she hadn't filed for divorce years ago. 

I strode into the shop with confidence, but then faltered. The cashier would realise I had driven all the way back just to retrieve the £3.50 I had been over-charged and think I was a right saddo.

I decided to make a purchase to cunningly give the impression I'd actually only come back because I'd forgotten something. 

I grabbed some broccoli and asparagus for £3 and headed to the same cashier.

'˜I'm sorry,' I said, wondering why I was apologising. 'But I've been charged full price for the first two items on this receipt when I think they should be half-price'. I let out a nervous chuckle.

'What?' the woman behind the till said. She was a charmer.

I repeated what I thought had been a pretty clear statement, then added: '˜To top it all off, I forgot to buy broccoli and asparagus, so I had to come back anyway'.

She shot me a look of utter contempt, then wordlessly jabbed at the pad on her till and said: '˜We'll refund you £3.50, tap your card against the machine.'

'Erm, I'm really sorry but the tapping thing doesn't work, I'll have to put it in,' I replied. This is true, most likely because I keep my card in my pocket and most of the magnetic strip has rubbed off. I've been meaning to order a replacement for about the last 19 months but have yet to get round to it.

The cashier '“ who was, weirdly, wearing gloves, like a serial killer might '“ audibly sighed. '˜Put your card in,' she barked.

'Have you charged me for the broccoli and asparagus?' I asked. She looked at me as if about to leap over the counter and batter me with a baseball bat, and said: 'Yes, I'm refunding the remaining 50 pence we owe you to your card, you pathetic little man'. The last four words I may have added in for dramatic effect.

It was only as I exited the store that I realised she hadn't once apologised for what was their mistake. At about the same moment I realised I had wasted an hour of my evening getting 50 pence back into my account.

I feel as though I may need to get a life, and to top it all I still have no idea what tempura means.