Why can't you do that in the UK?
If you look at what the Americans used to do (TN-C, and tying equipment chasis off to neutral), it answers your question. Live/neutral reversals and broken neutrals frequently resulted in people being electrocuted. Another problem is that when this was introduced along with polarized plugs and sockets, a lot of people ignored the advice in the manual, and went on to stick a nonpolarized plug on because their house hadn't been rewired. This results in 50% chance of a hot chasis. TN-C installs are still occaisionally found over there, where a two pin system has been converted to three pin sockets. But then USA is the same country that allows you to wire a grounded outlet into an ungrounded circuit, as long as it has RCD.
As knowing quite a lot about electronics, I have found it still, despite grounded outlets, very common practice to tie the neutral off at the chasis and leave it at that (it is allowed in many circumstances as opposed to grounding). Of course, us limeys know better...