Alternate fuel is not always required:
At least one destination alternate must be selected unless:
1. The duration of the flight does not exceed 6 hours or, in the event
of in-flight replanning, the remaining flying time to destination
does not exceed 2 hours; and
2. Two separate runways are available and useable at the
destination.
3. The appropriate weather reports or forecasts for the destination
aerodrome, or any combination thereof, indicate that for the
period from one hour before until one hour after the expected time
of arrival at the destination aerodrome, the ceiling will be at least
2,000 ft or circling height + 500 ft, whichever is greater, and the
visibility will be at least 5 km.
4. Additional holding fuel is carried Holding for 15 minutes at 1,500 ft in standard conditions at maximum structural landing weight.
(Source a UK airline's Ops manual part A)
Whats the Plan B if this two runway airport closes due to say a fire Eg Eddl a few years ago or LHBP if you want one with an alternate a bit further away.
All the eggs in one basket???