A bit more detail:
The BHX/LGW route was originally pioneered by British Caledonian on a Navajo Chieftan in order to increase passenger counts on its long haul flights from LGW as opposed to the competition from LHR. This service started in the 70's I believe and operating the Navajo was a route into the business for BCal's trainee pilots.
In the early 80's the route was taken over by Brymon on their Twin Otters (operated in single pilot mode, which the Otter is designed for - the RHS up front was a designated passenger seat, much fought for by the regulars). It was at one time the second most profitable route in Brymon Airways, but the introduction of mandatory double pilot crewing in 1990 meant that the Otter was no longer a viable aircraft for the route (due to it's passenger carrying capacity (17). The company replaced this with a leased SD 330 in about June 1990 but due to revised accounting proceedures it was declared that the route was no longer profitable and Brymon withdrew it during the November of that year. The remaining history of the route is as stated above. I understand that one of the main problems was landing charges at LGW. As it took almost as much runway time to get a Twin Otter on the ground as it took to get a 747, the airport preferred to get an additional 747 down or expected the 17 pax Twin Otter to pay the same fees! It was a great route - remember the press about the near miss that Concorde had with the Twin Otter - and the Twin Otter was right. It went on for years on the R.T: LATCC:" Morning Brymon, Concorde has just got airborne from Heathrow - and he's missed you!"
and so on.....
P.P.