R v L [2008] EWCA Crim 973, [2008] All ER (D) 66 (May)
There is no requirement that the police tell a wife that she is not a compellable witness against her husband before they interview her about a crime of which her husband is suspected.
If the wife subsequently refuses to testify, whether or not it is just to admit as hearsay evidence the statement she made to the police depends upon the facts of the individual case.