British Airways is offering a 3-day sale from all its Indian ports to London for booking till midnight of 27th July 2012, where it is offering flights from upwards of Rs. 52,000 for a round trip to London. The fare is valid on a 7-day advance fare booking.
I looked up the fare on their website, and it does look lucrative as compared to the regular British Airways fares from Delhi, Mumbai, Bangalore, Hyderabad and Chennai.
And they are not alone, seems like Virgin Atlantic has matched them on this route. Here is a screenshot of a sample fare from ITA for a Mumbai-London flight in November 2012, and Virgin Atlantic with their new product on the Airbus 330 will start flying to Mumbai again in October 2012.
Virgin is also cheaper on the Delhi London route.
Do note Air India is almost always cheaper and Jet Airways more expensive than the others. That has been my recent international experience with them where they price themselves higher than the other non-stop operators to the route.
So if you plan to be heading to London this fall/winter, right now is the time to act. You can book till tomorrow night midnight India Standard Time.