As of this week, the process to move from one broadband provider to another has changed (in most cases).
In the past, you had to obtain a code from your existing provider (called a "MAC"). You then provided this code to your new provider to initiate the migration.
From now on, the responsibilty for the migration lies entirely with the new provider. Once you have let them know that you want to move to their service, it will be their job to deal with your old provider.
One criticism of this new process is that there is now a compulsory 10 day notification period built into the switch. This means that it will not be possible to "rush through" a migration under any circumstances. However, this delay is necessary to enable the old provider to send a letter to confirm that provision is going to be switched. Without this step, there is a risk of a "slamming". Slamming a technique used by less scrupulous companies whereby they sign up a customer to their service without their full consent.
However, it does eliminate the need to have to sit on hold for hours to your old provider to get the necessary code from them, and we can't see many people complaining about that!