No idea, but it would only be fair to sent a bill. The RAF also scrambles up regularly (although mostly to intercept Russian bombers I think). How do they handle the cases involving civilian jets?

As for waste of this and that, I think the Air Force of most countries would really dread the paperwork they'd get into if they'd fired an air-to-air missile 

I do not think they will get a bill.  There was no actual breach of regulations by the aircraft pilots.
In fact in this case as communications were quickly established and the aircraft was following its correct track and tracked by radar as well as being observable by the civilian airline whose pilots filmed them the reaction was definitely overkill or an excuse to practice a procedure.

As they finally landed in Heathrow it shows there was no problem as all aircraft which are of concern are diverted to Gatwick which has special facilities and procedures for intercepted aircraft.

This is a totally clear case of the Air Force deciding to have a practice scramble.


Annex 10, Volume II is a large document but there are a few specific paragraphs about communications failure, shown below.



3.6.5.2.1 If in visual meteorological conditions, the aircraft shall:



a) continue to fly in visual meteorological conditions; land at the nearest suitable aerodrome; and report its arrival by the most expeditious means to the appropriate air traffic services unit;



b) if considered advisable, complete an IFR flight in accordance with 3.6.5.2.2.



3.6.5.2.2 If in instrument meteorological conditions or when the pilot of an IFR flight considers it inadvisable to complete the flight in accordance with 3.6.5.2.1 a), the aircraft shall:



a) unless otherwise prescribed on the basis of regional air navigation agreement, in airspace where radar is not used in the provision of air traffic control, maintain the last assigned speed and level, or minimum flight altitude if higher, for a period of 20 minutes following the aircraft's failure to report its position over a compulsory reporting point and thereafter adjust level and speed in accordance with the filed flight plan;



b) in airspace where radar is used in the provision of air traffic control, maintain the last assigned speed and level, or minimum flight altitude if higher, for a period of 7 minutes following:



1) the time the last assigned level or minimum flight altitude is reached; or



2) the time the transponder is set to Code 7600; or



3) the aircraft's failure to report its position over a compulsory reporting point;



whichever is later, and thereafter adjust level and speed in accordance with the filed flight plan;


code7700.com/pdfs/icao_annex_2.pdf

skybrary.aero/bookshelf/books/826.pdf
if you shoot them down evertime I think people may stop flying.