If you have had a bad experience with your current internet service provider (ISP), or perhaps just feel like getting a cheaper deal elsewhere, it is easy to switch to a different provider.  The process is called migration and starts by the account owner contacting the current ISP and asking for a MAC (Migration Authorization Code) key.  They are obliged under Ofcom rules to give you this free of charge within 5 days.  Always try to get this in writing - perhaps by e-mail, as it is common for codes read over the phone to contain errors such as differentiating between the letter O and the number 0, or the letter L and the number 1, or B and 8 etc.  A typical MAC key would be BBIP14175486/FA220

Be sure to say that you want to "migrate away" from the old ISP rather than cancel the service.  If you cancel, there will be a gap of about a week between provision by the old ISP and initial delivery by the new ISP.  Also, you will often be liable for a new activation charge.  Be prepared for the old ISP to do whatever they can to persuade you to change your mind.  It is necessary to be firm at this stage; when asked for the reason your are moving, an answer such as "I feel like a change for no reason in particular" is best for avoiding long discussions on why you should change your mind.  Remember that you are paying for the call, and if they are able to offer a better deal now you have decided to move, why didn't they offer it earlier ?

MAC keys are valid for 30 days and in that period you must choose your new provider.  Points to consider when comparing providers are shown in my considerations when choosing an ISP document.   The new ISP uses the MAC key to authorise the line provider to switch administrative responsibility from old to new ISPs.  The line provider is usually BT Wholesale but increasingly local loop unbundling is allowing other companies to provide the backbone infrastructure.

The existing ISP has to remove their marker tag from the line before a new service can be provided, and they normally do this after any outstanding fees are paid.  

Once you have chosen a new ISP they will give you a username and password to connect to their service, and this must be used to configure your modem or router when the cut-over day arrives.  Loss of service is usually just a few minutes while switching between old and new ISPs, and your new ISP should be ready to make the switch within 5 - 7 days of receiving the MAC key.

After you have started receiving service from the new ISP, it would be wise to confirm that no further payments are being taken or charged by the old. 

The process is usually very straight forward.  The only (minor) issue is that if your e-mail address is tied to your old provider, you will sometimes have to choose a new e-mail address. 

If you would like 1ComputerCare to take care of everything, just get the MAC key and stand back.  There is no charge to existing clients assuming no home visits are necessary.