LONDON, Feb 1 (Reuters) - Up to half a million British teachers, civil servants, and train drivers walked out over pay in the largest coordinated strike action for a decade on Wednesday, with unions threatening more disruption as the government digs its heels in over pay demands. His Conservative Party has been trailing the opposition Labour Party by as much as 25 percentage points in polls and surveys indicate the public think the government has handled the strikes badly. See here for a complete list of exchanges and delays