The Mayor's four year fare freeze famously means that bus and tube fares at the end of his first term will be the same as on the day he entered office. But that doesn't mean tube users won't be paying more, potentially 12% more.
Even though individual fares have remained the same, daily and weekly caps have continued to rise. They have to increase at the same rate as other National Rail fares across the country because a zone 6 journey might be on a train rather than the tube. This is how those caps have risen.
All-day cap (Oyster/contactless)
A small increase of 2-3% every year soon mounts up, and is equivalent to an increase of approximately 12% over four years. And this 12% rise might well apply to you, even if you only ever ride on tubes and buses where fares haven't risen. Here's how.
If your daily commute consists of a tube journey into town and another out, you never hit the cap, so that's fine. But suppose your commute involves a bus to the tube, i.e. two bus journeys and two tube journeys every day, then you're one of those losing out.
Example: A Z1-5 bus→tube/tube→bus commute
In 2016 the journey cost £1.50+£4.70+£4.70+£1.50=£12.40, but capped at £11.
In 2020 it'll still cost £1.50+£4.70+£4.70+£1.50=£12.40, but capped at £12.30.
A cap which once saved you £1.40 a day, now only saves 10p.
That's £1.30 worse off, every day, compared to four years ago.
Here's how the same calculation varies across all zones.
Daily cost of a bus→tube/tube→bus commute
In zone 6 we have now reached the stage where the daily cap is the cost of two tube journeys and two bus journeys, it isn't actually a cap at all.
Any other journey that breaks the daily cap will of course also cost you more in 2020 than 2016, not just the commute I've mentioned. Weekly capping has also risen similarly, again in the order of 12%.
It does mean TfL aren't losing out on quite so much fare revenue as they could be, which is good news for investment. But when you hear the 'fare freeze' being bandied about in the upcoming Mayoral election, remember that for many tube users it hasn't been a fare freeze at all.