If anything, Thatcher's move to get the government out of the coal business was prophetic in many more ways than she could have realized. The market for UK coal was non-existent: the resource was already dead to natural gas and oil.
The modernization strategies of Thatcher in the UK, Reagan in the US and even Mulroney in Canada were painful, but necessary requirements of countries that were trying to stay ahead of the curve.
The fact that the UK is a net importer of oil is irrelevant, given that this has more to do with high consumption than it does the industry itself.
One way or another the UK is going to pay for it's energy. The difference between the coal mines that Thatcher ditched and oil is that with the coal the UK was paying for that as well.
Oil prices? The current oil price and the oil price during the time of peak oil production of the North Sea fields is publicly available and googleable as are flow rates and production stats.
..or the fact that the West used oil prices as a weapon against the Soviets? Again a much-written about topic that you can do your own research on quite easily.
TheOilDrum.com has a lot of good links to info. What is the point that you deem controversial and in need of sourcing?
Edit: Oh wait, I see the point that you need a source for, that was Scottie in Star Trek.
Second Edit: Now, if this isn't just a rhetorical point of yours and if you are seriously interested in the oil industry and trends regarding North Sea production, and the problems the UK is facing because it flipped from 4th largest exporter in the world to net importer a few years back, I'm happy to chat about it and do the leg work to find you some interesting reads on that, but this post probably isn't the place for it (though I'll be blogging from richarddjordan.com as soon as I get by github pages set up, and you can always ask me there). It's a fascinating topic, and one that often takes people by surprise when they learn some of the rather concerning details.
http://en.wikipedia.org/wiki/Oil_and_gas_industry_in_the_Uni...
By all means though, if you want to undo Thatcher's actions and return the UK to a 19th century coal society, be my guest.
http://www.hi-energy.org.uk/Renewables/Why-Renewable-%20Ener...