They are talking levelised costs, which are always dependent on assumptions,which are rarely made explicit.
For resources like wind and nuclear power, interest rates are critical as most of the costs are up-front.

I tend to prefer installation costs, as they are less dependent on the assumptions made, but you have to allow for the fact that that is a bit unkind to renewables, as for nuclear power you have to allow for the long build times, and some fuel and maintenance costs ( maintenance has to be added to wind costs, and that can be substantial, especially for off-shore) and for coal or gas the fuel costs are the main cost.

So to answer your question, for on-shore wind the last survey which was done gave a cost of around £1million/MW of installed capacity, which does not include all connection costs or back up.
Since then material costs have risen substantially, and since most of the goods are imported the fall of sterling will have impacted costs.

This does not take account of wind's intermittency, so for on-shore you have around 22-28% of the installed capacity in actual output.

This effectively means that wind costs around £3 million/MW plus connection and backup at least to give a comparative figure to nuclear installed cost.

Off-shore is a disastrous £3 million/MW before you start allowing for intermittency.

Many of the more favourable figures quoted for wind are done after grants are added in - anything is cheap if you don't have to pay for it.

Here are the 2006 Government figures:
http://www.renewables-advisory-board.org.uk/vBulletin/attachment.php?s=0...