Upvote:0
I was in a similar conundrum last year. I travelled to SFO via LHR in Nov 2013, and was worried about the same thing. It isn't a problem. They will allow you to transit via Heathrow as long as the flight from India to London and from London to the US is on the same ticket.
My trip was even more complicated: I went from India to Paris, via LHR, and from Paris to SFO, via LHR. I didn't require a transit visa for any of these sojourns through Heathrow, since all these flights were on the same ticket, and my final destination was the US (for which I had a valid visa).
Upvote:2
The UK government is in the midst of porting their entire content into the gov.uk framework and UKVI is a part of that migration. Additionally, UKVI are revising large portions of their guidance, notably the Immigration Directorate Instructions and their entry clearance guidance. As a result, it's natural to expect some of the pages to be out-of-sync or missing altogether.
I do not know which consular site you found, but if the information conflicts with the gov.uk site, it's advisable to consider the gov.uk site as higher quality and more up-to-date. They are applying very rigorous quality control procedures for content on gov.uk.
The page you linked to (i.e., on the gov.uk site) is for airlines who are bringing people into the UK, and not necessarily for individuals. It's what airline staff will use to determine if you qualify to board the flight. It should be fully sync'd with other content on the gov.uk site.
So to answer your question, you should use the individual's page at https://www.gov.uk/check-uk-visa to determine if you need a Transit Visa as your primary source of information. Use the airline page for any additional information you might need. And avoid using the consular page if comparable information exists on the gov.uk site.