Most people want their letters to be effective, but some are not aware of how to achieve this.
A letter to the Prime Minister can:
reach the Prime Minister and be read by him, thereby conceivably producing some direct effect;
reach his political advisers, and possibly influence them; such a letter could also result in direct contact with one or more of the PM’s political advisors.
reach the public — as would a letter addressed to the PM and also published in the press.
Failure to do any of the above could mean that the effort expended on the letter was wholly wasted.
To get the Prime Minister to read your letter is the most difficult of the three. All the PM’s correspondence goes to the Privy Council Office and most letters are junked immediately, though there may be a count made on the question of who is for or against something such as missile defence. Many of the better letters receive a form letter by way of reply, and the PM never sees any of those either.
Then there are the few letters that receive personal replies. To increase the chances that your letter will be one of these, it is a good idea to send a copy of your letter to the person who handles the PM’s correspondence in the PM’s office. This indicates that you are not clueless about how things are done, and may also bring the Privy Council office back to have a second look at your letter, which so far had only reached the form-letter pile. They might reconsider and draft an individual reply.
The personal replies are drafted in the Privy Council Office and taken to the PM for signature with your original letter. The PM sees your letter at that moment, and you can be sure, the shorter it is, the more chance he will read it. Your letter must therefore not digress in any way from your main theme. It is also advisable to subject such a letter to a process of tightening. Get an editor to read it over and make suggestions.
It can also be very useful to reach the PM’s political advisors. To do this, address your letter to the PM in the usual way, but make sure you send a copy to his political advisor on that subject or to his chief political advsor.
Open letters are often intended to stir up public opinion, but it isn’t a bad idea if these also are subjected to tightening before sending. It is necessary to have someone willing to publish it about the time it is mailed to the PM.