30th June 2012, that is that the last date anybody registering a .co.uk or .org.uk will be entitled under the Nominet .uk proposal to have any rights at all for the equivalent .uk string.
There is likely to be over 1,000,000 UK domains registered since that date to the time nominet make .uk available, (if they launch it all) that will have no more rights than anybody else.
Nominet will also not tell anybody wether they even intend to contact the registrants of those domains, why would they have no rights!
Your observation on this point is very significant, but of course they can change the rules, if they proceed with .uk