Everyone who has ever crossed paths with the VAT man has a tale of woe to tell and Vince Cable now joins a large group of the chastened.

My brush with them came more than twenty years ago when, after a mildly successful patch as a freelancer, I thought I’d better register as I’d exceeded their turnover threshold. My slightly dozy accountant and I submitted the figures – offering to do my bit to fill Her Majesty’s coffers. My thanks was a nasty letter telling me I’d gone over the threshold two years before during a single financial quarter and I had to go back to all the publications I’d written for in the interim and demand they cough up the VAT. Otherwise I’d be put in the stocks. My customers were all thrilled about that, I can tell you. And I received a fine.

My relationship with the Customs and Excise took a further interesting turn when I received my first home visit to have a look at my books. Two guys appeared at the promised time on the doorstep which I interpreted as them arriving mob-handed. But it was subtler than that.

About an hour into the visit, while I was poring over my sales ledger with a desk covered in receipts, the older of the two VAT men quietly told me the young guy was his manager and was in tow because he was on his final warning for poor performance. They wanted him fired for failing to squeeze enough balls until the owners coughed up. Being a touch disorganised when it came to bank statements and bookkeeping I was proving a nightmare case. I felt sorry for the poor guy and did my best to make him look good.

HMRC was the product of a merger between the Inland Revenue and Customs and Excise which took place in 2005 and brought together two very different cultures. Customs people often saw themselves as a branch of law enforcement with a proud history stretching back hundreds of years to when they chased rum smugglers around the Dover cliffs. They still do a fair bit of kicking down doors and feeling collars which I’m sure they hugely enjoy.

They pride themselves on a thorough-going approach as I discovered when I once spent a day with them on the Customs front line at Stansted airport. Their pride and joy was a transparent plastic lavatory on a dais on which suspected ‘stuffers’ were made to sit until they evacuated their bowel with their condoms filled with cocaine or heroin.

No such instrument of Number Two torture for the Revenue. In my limited dealings with them I’ve always found revenue folk extremely polite and helpful. My tax office is in the North East and they couldn’t be more accommodating. I daresay if the saintly Cable had fallen foul of them it would have been little more venomous than a “Now what’s gone wrong here then, pet?”

I’ve been taking some stick for some comments I made about the Royal Mail on BBC Radio Five Live’s On The Money on Sunday night. The point I made, fairly forcefully, was that if anyone thinks that Vince Cable’s masterplan to hand over 10% of the shares to the posties is suddenly going to turn the Royal Mail into a John Lewis-style organisation of harmony and commercial efficiency, they have another thing coming.

John Lewis has taken decades to evolve into the success story it is now. Its employees also own 100% of the organisation and are not able to offload their share-holding within a couple of years of receiving it for a quick few grand to blow on a holiday. When they voted on becoming a PLC in 1999 – a move which would have given the John Lewis partners a windfall of £100,000 each – it was rejected.

But the problem is far deeper than this. The central issue is one of culture and by this measure the two organisations are from different planets. I illustrated this by the example of Ocado drivers – still part-owned by John Lewis and steeped in its values – and Royal Mail vans, mostly driven, in my experience, by guys who think they are appearing in Mad Max.

You never see an Ocado van going over 27 mph; they always let you turn in front of them into traffic. They are, in short, superbly well trained in being brand ambassadors. By contrast the Mail drivers whizz down our road – which is a 20 mph zone – at speeds often in excess of 40 mph, scaring all of us witless. On several occasions when I’ve remonstrated with them about this, I got a twenty second burst of the vilest profanity, followed by the finger. Try to get in touch with the organisation to point out that this isn’t acceptable behaviour and you’re met with a dead end.

And don’t get me started about the alacrity with which they bung their ‘we tried to deliver this but you were out’ postcards through the door and then make you queue for 45 mins on a Saturday morning to get your Amazon book (I now get everything delivered to work).

The Royal Mail has an ugly, confrontational workplace culture. And this is too often the face that it presents to the public, especially in cities. At its worst the unionised workforce is deeply suspicious of management, resistant to change and very hard to control. The management is often weak and ineffective. But everyone knows that if it doesn’t modernise its work-practices to take account of changing technology and communications behaviour then it is finished.

It’s not all The Royal Mail’s fault. Its remit is dictated by politicians, not the market. It’s a public service with all the grief that involves. There is no way, in the future, that charging the same to send a letter from Watford to Stornaway should cost the same and take the same amount of time to deliver as from Watford to Luton. Neither DHL nor Fedex think so. And Ocado doesn’t deliver to Stornaway anyway.