For your information......
Home Office Guidance for the Police.
(Sorry it prints out in this way.)
It is 'guidance' because there is no actual law that says that you have to have a cabinet. The Home Office basically says under lock and key or words to that effect.
However the following is what it issues to the Police Forces. It is a 122 page document so i have only taken the relevant bit ....hope it helps. (UK only).
FIREARMS LAW
GUIDANCE TO THE POLICE
Chapter 19
SECURITY OF FIREARMS AND AMMUNITION
Siting and fixing of devices
19.38 Any firearm security cabinet etc. should
be sited out of view from people both inside
and outside the building. Securing to suitable
building walls within built-in furnishings, that
is wardrobes, cupboards, lockers etc. can
prove effective. Rooms such as lofts and
cellars for example, that are unlikely to be
visited by casual visitors, are an option.
However, when recommending such places,
it is important to consider whether the
environment is suitable. Extremes in
temperature, dampness, condensation etc. may
militate against such use, as not only could
it result in damage to the firearms and
ammunition but particularly in damp areas,
it may cause erosion of the fixings or the
cabinet material, thus reducing its security.
19.39 In addition, the ease and convenience
of access to such places is important. If this
is difficult there may be a tendency for the
certificate holder to delay putting their
firearms away upon return to the dwelling.
Police research has shown that a number of
losses have involved owners not immediately
securing their weapons and suffering their
subsequent theft.
19.40 In advising on the location of any
security cabinet, remember that most steel
gun cabinets have a high weight-to-footprint
ratio. The average floor loading for a
suspended floor on timber joists is 56lbs
per square foot. A 9-gun cabinet with a
24" x 12" (60.1 x 30.1 cm) footprint can
be in the order of 126 lbs per square foot
which equates to more than a safe average
suspended floor loading. Obviously, any
fixing to a wall will reduce this loading.
Joist ends are a more suitable fixing location
than joist runs.
19.41 In a loft installation for a cabinet, care
needs to be exercised. Not all lofts have
joists calculated to include weight loading
other than that of the ceiling below. It is not
uncommon for joists in lofts to be 40%
smaller in cross sections than joists carrying
floors. Full use must therefore be made of
the support from structural walls carrying
such joists. If there is any doubt, the
applicant/certificate holder should obtain
proper structural advice.
19.42 Fixings for security devices form an
important part of the overall resistance to
attack. Fastening to timber studded walls
should be avoided, unless some additional
anchorage can be provided. Floor or roof
joists (subject to the previous comments) are
acceptable. Walls of brick, concrete or
masonry are usually the best bonding
materials. It is important that the fixing bolts
chosen are correct for that material (for
example expanding bolts, chemical anchors,
toggle bolts etc.). With modern building
materials, particularly breeze and thermal
block walls, the materials are not particularly
suited to normal fixing devices.
19.43 When cabinets are being fitted,
consideration should be given to varying the
method of fixing. For example, in buildings
with only partition internal walls and modern
insulation block lining or random stone walls,
it can be perfectly acceptable to fix cabinets
horizontally, as long as appropriate fixing
devices are used.
19.44 This will also assist when fastening into
suspended wooden flooring, as it spreads the
load more evenly. In this case, coach screws
of at least 3/8" (9.5mm) diameter and not
less than 2.5" (63.5mm) long will normally
provide a suitable anchorage. However, where
screws of such a size might weaken the
suspended flooring, smaller screws might
be more appropriate. Such fixings must of
course be made into joists and not simply
to the floor boarding.
19.45 Another consideration should be the
size and weight of the larger form of gun
cabinet or commercial safe. Due to their very
weight or size, fixing may be unnecessary in
these cases, but they should be located in
such a position that would further frustrate
removal.