Royal Mail has announced new postal rates to take effect on April 7. The basic first-class rate increases 2p to 36p, but the second-class rate has a much larger (on a percentage basis) increase, a 3p jump to 27p.
The international rates also increase, though overall by a smaller percentage than last year. The basic rate to Europe rises from 48p to 50p and the first two airmail rates go from 54p to 56p for 10 grams and 78p to 81p for 20 grams.
There's more information about the new rates on my web site.
There will be only three new Machins, a smaller number than the five last year. (One of those was the 50p in a new color, so the rate change really only required four new Machins. I'm not counting the new printing of the 46p Machin which also occurred last year.)
There will be a 56p lime green and an 81p sea green for the new international rates. There will also be a 15p shocking pink to pay the difference between second-class letters (27p) and second-class large letters (42p). The difference between first-class letters and large letters is now 16p, and that is paid by the 16p Machin issued last year.
(It is interesting that shocking pink was picked for the 15p because the 16p is pink, the new non-shocking shade developed a few years ago by Jeffery Matthews. It will be easy to confuse the two values, I think.)
Royal Mail also notes that the 9p orange will be put back on general sale to pay the difference between the 27p second-class and 36p first-class rate. As has been common practice, the 9p was withdrawn from public sale last year when it was no longer needed, but it remains on sale to collectors from Tallents House. Royal Mail hasn't announced whether there will be a new printing of the 9p that is distinguishable from the previous one, as there was last year with the 46p.
There are two other items to note, although these don't have to do with Machins. First, there will be new regional definitives in 50p and 81p denominations, keeping the same designs that have been used for many years.
Second, Royal Mail has simplified the worldwide airmail rates for mail going to destinations other than Europe. Previously there were two zones, and letters weighing more than 20g were charged a higher rate for zone 2 than for zone 1. Starting on April 7, there is only one zone for such mail, and the new rates are in between the old zone 1 and zone 2 rates. More details about the zones can be found on the Great Britain Collectors Club web site.
Update: Here's a glimpse of the new Machins.