dizzy@desktop:~$ host nofourth.co.ukCoincidence? Maybe. There is a guy called Chris Birks that is linked to Conservative Future. A relative maybe? Who knows!
nofourth.co.uk has address 184.108.40.206
dizzy@desktop:~$ host labourist.org
labourist.org has address 220.127.116.11
UPDATE: I see Labourist's navbar has started to link to No Fourth as well.
UPDATE II: As pointed out in the comments, each "slice" of hosting on the provider for these sites gets it own IP address so the fact they share an IP means either (a) Labourist and Nofourth are run/designed by the same person or (b) Labourist has provided free hosting to Nofourth.
UPDATE III: Matthew Birks has posted a comment on Unity's blog saying he has nothing to do with Chris Birks, but no denying he has anything to with Labourist. It's also worth noting that Chris Birks also appears to have been fibbing somewhat about his former life as a BNP activist before joining the Tory Party.