The actor Tom Cruise has been in damage control this week after a video showing him extolling the virtues of Scientology spread across the internet.

The appearance of the nine-minute clip coincided with the publication of Andrew Morton's book Tom Cruise: An Unauthorised Biography, which alleges that Cruise ranks second in command in the Church of Scientology.

On the video, Cruise is shown speaking about the religion while the soundtrack to his Mission: Impossible films plays in the background.

"It's rough and tumble, and it's wild and woolly and it's a blast," he says. "It's a blast. It really is fun, because ... there is nothing better than ... going out there and fighting the fight and, suddenly you see, things are better."

Scientology lawyers fired off letters to Morton's publisher and have demanded that Gawker.com - a website running the Cruise video - remove the clip, alleging breach of copyright.

Nick Denton, on Gawker.com, replied: "It's newsworthy, and we will not be removing it."

Scientologists did force YouTube to remove footage of Cruise's rant. YouTube posted a message above a still of the clip, saying: "This video is no longer available due to a copyright claim."

But by then millions of people had seen it and it had spread to other websites.

On the video, dressed in a black turtleneck sweater with a look of intensity in his eyes, the 45-year-old Cruise makes a series of impassioned claims about his religion, including its ability to help get people off drugs, rehabilitate criminals and "bring peace and unite cultures".

Here is a transcript of Cruise's remarks:

I think it's a privilege to call yourself a Scientologist, and it's something that you have to earn because a Scientologist does - he or she - have the ability to create new and better realities and improve conditions.

Ah, being a Scientologist you look at someone and you know absolutely that you can help them, so for me it really is KSW [keeping Scientology working] and it's just like it's something that, ah, I don't mince words with that, with anything, but that policy has really gone, boy, the first time I went through and went, you know what, when I read it I went, you know, this is it, this is exactly it.

Being a Scientologist when you drive past an accident it's not like anyone else, it's you drive past and you know you have to do something about it because you know you're the only one that can really help.

But that's what drives me. I know that we have an opportunity to really help for the first time effectively change people's lives and I am dedicated. I am absolutely uncompromisingly dedicated to that.