You know who they are. Those people that you just dread calling you, like your bank manager, boss or ex-girlfriend. When they call you normally only have a limited number of options: you can answer the call (out of the question), let it ring off (embarrassing if you're on a crowded train), or 'red button' them (which will rile them even more than not answering). Face it, you're screwed either way.

Actually, you're not. Well, not if you install iBerry Black & Whitelist on your Blackberry phone, anyway. As the name suggests, the application allows you to 'blacklist' people who you don't want to speak to and 'whitelist' those that you do.

Creating blacklists and whitelists is a simple task that can be done in a number of ways. You can either add numbers to the lists from your contacts, or go through your call logs and mark them as black or white using the appropriate radio button. You can also choose to blacklist anyone whose number is hidden when they call.

The software works effectively, and disconnects the phone within 50 milliseconds of a call coming through, leaving your caller unaware that they've been blacklisted - they'll just think that your phone is switched off. Your Blackberry won't make a sound or vibrate, so you won't even know about it until you check your call logs.

There are loads of options and blocking settings to tinker with, so the menus get a little cluttered, but once you've worked out the way you want to block people, you learn to ignore the ones you don't need.

An effective solution for blocking unwanted callers.