The northern Indian city of Amritsar will be served three times a week by Bmi starting on October 13.
Flights, which are still subject to government approval, will be operated by an A330 with an en route stop in Almaty, Kazakhstan.
The aircraft is configured with 36 business (60 ins of legroom with 50 degree angle of recline) and 196 economy class seats (32 ins of legroom).
Flight BD991 will depart from Heathrow on Monday, Thursday and Saturday at 9.55am, arriving into Almaty at 11.20pm. The second leg of the flight will see a 00.10am departure from Almaty, and a 2.45am arrival into Amritsar.
From Amritsar, flight BD992 will leave at 4.10am on Tuesday, Friday and Sunday, arriving into Almaty at 7.45am, then leaving at 8.45am and arriving into Heathrow at 10.50am.
Bmi previously served Mumbai in the days following airline liberalisation in India, but the route was subsequently dropped.
Amritsar was previously served non-stop from London in 2006 by Jet Airways, but that route too was dropped some time later.
Bmi believes it can succeed on this occasion because it is spreading its risks. The canny carrier is managing to serve Amritsar by simply extending an existing route (London-Almaty).
Flight time between Almaty and Amritsar is only 2 hours 40 mins so the increased operating costs will be minimal compared to the expense of flying London-Amritsar non-stop.
www.flybmi.com