Postage rates are increasing again at the end of this month.

From the Royal Mail:

The price of a 1st Class stamp will increase 2p to 62p.
A 2nd Class stamp will increase by 3p to 53p.
The price of a 1st Class Large Letter stamp up to 100g will rise by 3p to 93p and a 2nd Class Large Letter will rise by 4p to 73p.
…
Full details of all our price changes, including the cost of sending parcels, are available at www.royalmail.com/prices2014

Please note that the message was received from the Royal Mail by email, not by post!

As for the Royal Mail, so the Challenge - it is likely that many more Challenge communications will fly by email rather than by post in future; in most instances only the Event Details and the Final Details – and perhaps the Final Report – are currently posted.

Preaching to the converted by posting on a message board I expect but thought a heads-up might be in order.