Manchester United’s purchase of Rio Ferdinand from Leeds proves several things, not least of which is that we now know there is no transfer on earth that can be prevented by factors of tribalism, allegiance, “loyalty” and all that shite. I suppose that Luis Figo’s move to Real Madrid two years ago had already proved this dictum with some force, but the Ferdinand deal re-emphasised it one more time with feeling.

Not the least edifying aspect of the whole affair was the wonderful sight of apoplectic Leeds fans choking back the vomit as they saw their prize asset heading across the Pennines with barely a wave goodbye, combined with the dawning realisation that they are now effectively a feeder club for Man U.

We have, of course, seen this movie before, with Gordon McQueen and, more celebratedly, Eric Cantona making the same journey in times past (although Denis Irwin did not come from Leeds to Old Trafford, as was erroneously reported in some newspapers – he was signed from Oldham).

What are they moaning for anyway? Didn’t we give them John Giles and Gordon Strachan? What do they want, blood? Probably.

Ferdinand has been called everything from a Judas to a scumbag in the past fortnight by Leeds’ legendarily fair-minded supporters, one of whom responded to the news of his hero’s defection by hanging a club shirt on the Elland Road gates with the word “LOYALTY” written where Ferdinand’s name should have been.

Christ, if we were applying this loyalty thing to the letter then Ferdinand would have stayed at West Ham for the rest of his life. Instead, he fucked off when a bigger club came calling, because he’d had three years solid of finishing ninth in the Premiership, and had had a bellyful of it.

As we know, Manchester United are as big a step up from Leeds as Leeds are from West Ham, and the loyalty thing never becomes an issue where United’s own players are concerned, because they are such a huge and powerful outfit that a move away from Old Trafford to any other other club (save, perhaps, Real Madrid) could only be a step down the footballing food chain. When a player leaves United, it’s because they’ve finished with him, not the other way around.

Now we can turn our minds to the question of what exactly United are getting for their stg£30 million, or stg£29.2 million, or whatever the fee turns out to be when adjusted for inflation and the euro’s parity with the dollar.

It seems patently obvious that Ferdinand is not the infallible, Beckenbaueresque colossus that he was repeatedly written up as during the World Cup finals. It seems equally obvious, however, that he is now unrecognisable as the hesitant, slightly ponderous player that struggled through Leeds’ early Champions League assignments two seasons back.

I may as well confess that I only saw three-and-a-bit of England’s (and Ferdinand’s) five games in the World Cup. The Nigeria match, as well as having 0-0 written all over it in advance, was a 7.30am kick-off, so there was no option but to give it a miss; and I switched off the Denmark game when England went two up.

But Ferdinand, along with Nicky Butt and (gulp) Danny Mills, represented one of the few genuine pluses of England’s wretchedly unimaginative showing. His display against Argentina, when he put in enough challenges, tackles, blocks and clearances for six matches, was probably the individual defensive performance of the tournament.

In short, Ferdinand was pretty damn good in a World Cup not overburdened with top-drawer centre-backs. He was made to look even better than he was by the inadequacies of most of the other central defenders on show. (The above also applies, to a lesser extent, to Gary Breen.)

This ensured that when Ferdinand returned home, he got the best reviews since penicillin. It was understandable that the English press should be eager to seize upon what was practically the only positive aspect of their World Cup campaign, but that’s no excuse for the gushing torrent of hyperbole that ensued.

Time for some perspective. The best defender Foul Play has ever seen in his life was Franco Baresi. Compared with that fellow, Ferdinand is practically playing a different sport.

And he’s not the best centre-back in the Premiership, either. That accolade belongs to Sami Hyypia, until we see some sustained evidence to the contrary.

But from a United perspective, he’ll certainly do for now. He’ll bring serious solidity and presence to a back four that has been, frankly, terrible for a good two years now.

Of all United’s defenders, only Gary Neville performed creditably and consistently last season. Laurent Blanc had his moments, but you still wouldn’t want to be depending on him in a tight corner. The best that can be said of Phil Neville and Mikael Silvestre, meanwhile, is that they never descended to the depths scaled by the hapless Wes Brown, who nonetheless somehow still made it into England’s World Cup squad.

Now that Ronny Johnsen and Denis Irwin have been consigned to oblivion (or, in Irwin’s case, Wolverhampton, which amounts to the same thing), United need all the warm bodies in defence that they can get.

With Ferdinand on board, things look rather less gloomy in that department than they have for some time. And did I mention John O’Shea, now poised to make a genuine breakthrough into the United first team after three years of watching and waiting?

It’s probably too late for United to reinvent themselves as the parsimonious, nine-behind-the-ball 1-0 merchants of the Premiership (that’s Liverpool’s job, of course), but let’s see what happens.