It is exclusive run by the Daily Telegraph that HTC Google Nexus One will be launched in the UK this April. It will be on sale through Google's Nexus One site. The price of the phone has not been disclosed as yet but it is expected to be priced similar to what the US market is offering ($529 exclusive of shipping and taxes).
Although the exact date is yet to be announced but both, Google and Vodafone, officials have confirmed the Telegraph about the possible launch readiness by April. Vodafone was pushing for March but it seems that now they would like to launch it within the Spring season, as they say.
Source: Daily Telegraph