"However, since the uranium available in the UK is nil, this cannot be the solution to all our power needs."
I wouldn't worry as much about being dependent on Canada or Australia as I am about being dependent on russian gas or middle eastern oil.
Uranium is not hard to stockpile many years into the future; it's some 100 tonnes of low enriched uranium dioxide pellets per 1 GW reactor per year.
"If nuclear is so safe, why must government pay to ensure safety?"
Government doesn't pay for safety; it holds nuclear energy to an extremely high regulatory burden and safety standard compared to every other power source for which utillities pay through the nose.
"If nuclear is so cheap, why must government subsidise it?"
Nuclear energy is held to an irrationally high standard motivated by fear and nuclear exceptionalism rather than actual safety arguments. That hurts far more than subsidies help.
Coal kills some 20 000- 40 000 people per year in the US according to the EPA, gets to release enormous quantities of CO2, mercury(which unlike spent fuel doesn't disappear if you wait long enough); no one bats an eye-lash. You could literally dump spent nuclear fuel straight in the ocean with no precautions, no containment whatsoever, use the LNT model(which is an overestimate at low dose rates; but its use is still required by law) to estimate the death toll over eons and you would still not get anywhere near the death toll of coal energy.
Yet spent nuclear fuel is somehow too dangerous to salvage the useful components(platinum group metals, reactor grade plutonium, remaining U-235, possibly technitium which would be very valuable as a catalyst and is only mildly radioactive etc.) and must be burried immediately.
The likely death toll if a spent fuel cask ever broke in a crash is zero(from radioactivity, not the crash); it's a high density ceramic with a high melting point and it will just sit there until the experts come clean it up(wait till you see the bill). A truck or train car carrying anhydrous ammonia, chlorine or any number of other common industrial chemicals is far more dangerous if the tank were ever to rupture(and they do quite frequently. it's not uncommon for a dozen or so people to die and thousands of people to be evacuated); yet they're allowed to carry this stuff in an oversized coca cola can when spent nuclear fuel has to be carried in a cask capable of surviving not only a high speed crash, but being dropped on a spike and then being incinerated for hours and still passing a helium leak test.
When a reactor leaks some tritium, equivalent in exposure for nearby inhabitants to eating a banana and far less than going to the dentist or living near a coal plant for a few days, there's an investigation and it's reported in the news as some kind of serious accident.
Enormous costs have been piled onto nuclear energy by "environmentalists" in the name of safety(strange how often they turn out to have ties to coal and natural gas interests). If safety was the real concern here you could get far better returns on your investment if stopped flushing this money down the toilet and spent it elsewhere; e.g. forcing roofers to wear a safety harness, a wear your seat-belt ad campaign or a publically funded search for new anti-biotics.