PETER Solly (South China Morning Post, February 8) questions the need for some police officers to carry machine guns while patrolling ''friendly'' Kai Tak Airport.

Their presence in the Airport Terminal Building is to ensure an instant armed and uniformed response to any incident which may affect the security of the airport.

All Airport Security Unit officers are highly trained in the use of the weapons they carry and their presence is considered a useful deterrent to any would-be terrorist or other violent criminal.