Would it be possible to make a fake 45 gun out of modelling clay?

What matters most is the intention behind the use of an object, not its actual purpose. For example, in Russia, Kazakhstan, and many other countries of the former Russian Empire, ordinary people are allowed to carry any knives, including machetes, on the streets, except at rallies, concerts, and the like. However, committing a crime using even nail scissors or a child's Jedi sword as a weapon would be considered a crime involving the use of a weapon.

One should always use common sense and not look for threats where there is clearly none.

UK has screwed up miserably by not creating its own national social network, as many civilized countries have done. There simply isn't a national alternative to Facebook.