It depends on how modern the aircraft is. The MOD would remove any ‘sensitive’ items such as avionics that were ‘classified’ and manufacturers may wish to protect their ‘intellectual property’.

For example the recently retired Sea Harriers had their radars removed.

I think there is a camera displayed with the SR71 at Duxford but I’m sure it’s older obsolete technology.

Of course any dangerous items should be removed – ejection seat pyrotechnics, canopy detonation cords, avionics demolition devices (where fitted) and cable cutters (on older aircraft).

WA$.