Bobbys
Here's what the web site has to say
Do I Need A UK Visa
You asked if a national of India needs a visa to pass through the UK in transit.
Yes, you need a Direct Airside Transit (DAT) visa, unless you qualify for exemption because you hold one of the following:
a valid US/Canadian visa and also hold a ticket to or from the US/Canada routed via the UK. This will include a period of 48 hours after the expiry of the US/Canadian visa for those leaving the US or Canada to allow for those who choose to leave at the very end of the validity of their visa;
a USA I - 551 Permanent Residence Card (Green Card) issued on or after 21 April 1998;
a US Immigrant Visa and Alien Registration - Form 155
an expired I - 551 Permanent Residence Card and a valid letter authorising its extension from a US Embassy/Consulate;
a Canadian Permanent Residence Card issued on or after 28 June 2002;
a valid Category D visa issued by EU/EEA member states;
a common format EU residence permit issued under Council Regulation (EC) No 1030/2002.
Nationals of certain countries, which includes India - unless exempt as detailed above - must have a DAT visa to transit through the United Kingdom. The visa does not allow entry to the UK: other than to catch a connecting flight, leaving from the same airport on the same day, where you do not need to pass through immigration control to catch the flight. This is called Direct Airside Transit.
You could check it as well
http://www.ukvisas.gov.uk/servlet/F...t/Xcelerate/ShowPage&c=Page&cid=1006977149962