As you've been told, Flash is not available on any iOS device.
To read why it is not go here:
http://www.apple.com/hotnews/thoughts-on-flash/
To tell Apple you disagree and would like to have it on your iPhone go here:
http://www.apple.com/feedback/iphone.html
You might also want to contact 4oD and advise them you would like to be able to watch a programme on your iPhone. There are other open source means they can utilize to do so.
You can also enter the word "Flash" in that box over to the right that says Search Discussions and read many threads about this topic. I highly recommend doing so if you suffer from insomnia. You'll get to sleep in no time.
You can also use the workaround already suggested, i.e. Skyfire, or one of the remote applications in the app store such as SplashTop Remote.
Past this there is really nothing more anyone can tell you except that if you REALLY, REALLY need Flash on your phone look for a competing smartphone such as one of the Android series. Check first.