I am flying out to New Delhi from London for one month and this would be the last visit on my current tourist visa which I have. There may be plans to extend my stay and there is no problem apart from the fact that if I wanted to stay then my visa would expire and obviously I need a valid visa. Is it a possible to extend my India visa on my British passport while I am in India? Where can I get the visa extension from in India? How long will the procedure take and how long before do I need to apply for the visa?
I am not aware of any options to extend a visitor visa. Those people who over stay have to get an exit permit which carries a little fee so I am guessing thats what you would need.
I don't know about extending a visitor visa, unless you have a valid and good enough reason you should be able to apply for a visa extension, but the best place to ask would be at the nearest FRRO office near you, where visa extensions are given.
You should not wait until your tourist visa expires, just get a new one. There’s no case in traveling if your visa is going to expire and you would need to fly home at the middle of your trip. Just get a new tourist visa before flying.