SO there I was, all set to write an angry piece about Boris Johnson's "massive fare rises." (The fare changes happen tomorrow, by the way). But then I thought: you know, I'd better check the new fares, hadn't I?

And guess what? If I use my new Oyster card, the ticket I most often buy (an off-peak single from Greenwich to London) hasn't gone up at all. It has in fact fallen - by nearly 30 per cent, from £2.40 to £1.70. (If I travel in the peak, it will be £2.10 - still a reduction of 12.5 per cent.)

Maze Hill, Westcombe Park and Blackheath single fares fall even further, by up to 35%.

The ticket I occasionally buy (an off-peak return from Greenwich to London) hasn't gone up either. It too has fallen, by 3 per cent, from £3.50 to £3.40. Peak returns have fallen by 2 per cent, from £4.30 to £4.20.

Maze Hill, Westcombe Park and Blackheath return fares fall by 2.5 per cent.

The ticket I always used to buy before I got a bike (a one-day Travelcard) hasn't gone up. It is still £5.60. The tickets I would buy if I commuted to work by train - period Travelcards - haven't gone up. They are the same price, too. All this applies almost universally across the zones, by the way.

In other words, virtually every National Rail journey in Greater London will in fact be cheaper, in real terms, this year than it was last year.

It really does serve me right for believing this recent attempt by a declared political partisan to spin the change as "London's great train robbery" in which "voiceless commuters get screwed again."

Of course, if you look hard enough, like he does, you can find someone who's going to pay more. But you do have to look pretty hard (in this case, someone who decides to carry on buying off-peak returns on a paper ticket will indeed pay more).

Or you have to be deliberately misleading. Look, for instance, at that sly reference to evening peak single fares being higher than off-peak for the first time; no mention of the fact that even the evening peak fares will still be lower than they are now.

Look, to take another example, at the claim that "South London families" will "lose out in [the] Oyster upgrade." Well, it's true that a concession on the Tubes allowing under-10s to travel for free with an adult is not going to be extended to the National Rail network south of the river. But since we never had such a concession in the first place, it is not something that we have "lost in the Oyster upgrade," is it?

You have, I suppose, to admire the hours which must have been spent combing through the detail in order to find examples this obscure. But the desired political effect is likely to be rather short-term. Because from tomorrow, real train passengers will start paying real fares. And when almost all of them find that, contrary to the propaganda, their prices have not gone up, it's going to hurt the credibility of the wolf-cryers.

The benefits of Oyster are not just limited to lower fares, either. Never again will I have to allow five minutes to buy a ticket. Never again will I have time-consuming confrontations with penalty-fare Nazis at the other end.

There certainly are losers from tomorrow's fare changes - on the buses, where the single fare rises by 20 per cent. A headline about Greenwich's "great bus robbery" would have been honest - and might also have provided a genuine attack line about Boris's cynicism in holding down the fares of rail commuters while hammering bus passengers, who tend to be rather poorer and less Tory-voting.

But for rail users in general and Greenwich rail users in particular, this is a boon. Just remember your little piece of blue plastic.

Rail fares (Oyster) to London from...