We own a magazine lets say 'x' in India, and there is a huge demand for it in UK. In order to meet the demand we have decided to publish 'X' there.
What rules am I supposed to follow? Does the UK copyright act say anything about such actions?
This will fall under licensing of copyright correct?
Since I assume that you own the copyright in the Indian edition, then there is no problem with you publishing a UK edition also. The UK edition will be fully protected in the same way as any other UK magazine. I also assume that this magazine is to be printed as opposed to something provided online in electronic format.
You didn't mention whether the UK version would be printed in the UK or be printed and shipped in from India, but this makes a very slight legal difference because in the later case, the place of publication would be India. If the magazine is to be printed in the UK and there are significant differences (say in the layout, or language used) then the UK edition would be a 'new' work with a separate copyright status compared to a copy of the Indian edition which was imported. Incidentally there would be other ramifications from this issue, including the law on defamation.
There are two aspects to copyright. Copyright in the published edition as a whole and copyright in the individual articles and illustrations etc.
As far as I am aware Indian copyright law does not provide copyright for a printed edition; in the UK this right exists for 25 years from the date of publication and essentially protects the typographical layout, and is owned by the publisher. Ownership of copyright in the individual articles and photographs etc will be depend on whether the writer/journalist/ photographer/illustrator was an employee of the publisher or a freelance contributor. The rules on ownership are fundamentally the same in both countries. As works made in India only enjoy a copyright term of the author's lifetime plus 60 years (as opposed to plus 70 years in the UK) the Indian term will also apply to magazine content published in the UK. There is one difference. In the UK photographs enjoy the same protection as other types of work (ie the author's lifetime plus 70 years), but in India the term for photographs is 60 years from the date they are created. This shorter Indian term would apply also in the UK for any photographs which originated from India and appeared in the magazine.
You mentioned licensing. If you don't want to publish the UK edition yourself, you can appoint a licensee in the UK to do this. As this would need a fairly carefully drafted contract to implement, covering far more than just copyright issues, you would need to engage a UK lawyer to handle the details.
There are a couple of other miscellaneous things you need to be aware of if you publish in the UK.
Depending on the type of content and the frequency in which issues are published, your magazine may fall within the definition of a 'newspaper' and thus be subject to the Newspaper Libel and Registration Act 1881. You can find more details about what this might mean for you, here. Secondly any edition published in the UK is subject to the Legal Deposit Libraries Act 2003. In simple terms, this means you as the publisher would be responsible for delivering a copy of each issue to the 6 Legal Deposit Libraries* in the UK and Ireland. If your magazine is to be published in electronic format, then special rules apply to the Legal Deposit Libraries obligation. And finally, unlike India, there are no official provisions for registering copyright in the UK. However this unlikely to have any effect on your ability to prove ownership of the copyright should this become necessary.
* The Legal Deposit Libraries are: the British Library, the National Library of Scotland, the National Library of Wales, the Bodleian Library Oxford, the University Library Cambridge, and the Library of Trinity College Dublin. Technically speaking the last five institutions need to request that copies are made available to them if they want them. However a publisher does need to notify all the Deposit Libraries.