The humble 'second class' stamp has been in existence in the UK since 1968 when the old system was replace with first and second class deliveries.
Originally intended to be a system where first class was delivered the very next day and second class a day or so later it has, over time, morphed into one.
So right now if you pop a second class letter and a first class letter into the same post box at the same time going to the same destination the chances are that they will both arrive at the same time.
The drop in mail volumes since the introduction of electronic communications has meant rationalisation in the Postal System and where there used to be separate treatment for ‘First Class Stamps’ and ‘Second Class Stamps’ today they typically end up in the same bag together.
The result is that the humble second class stamp is actually as powerful as it’s bigger first class brother these days and at 9p cheaper currently (October 2015) if you are sending a lot of mail it can be a big saving.
So celebrate the second class stamp; it’s been a workhorse of the British Postal System for almost 50 years and should be recognised for its sterling efforts.