MADRID, Oct 23 (Reuters) - Spain’s Sabadell said on Saturday its board had rejected an offer from Co-operative bank for its British subsidiary TSB after Sky News first reported about the approach. Sabadell confirmed in a statement that it had received a letter from the Co-op bank outlining a proposed offer for TSB. However, the Spanish lender said that its board had officially responded to Co-operative bank that “this is not a transaction that we wish to explore at this moment as we have previously expressed publicly.” (Reporting by Jesús Aguado; Editing by Emma Pinedo and Jessica Jones) Our Standards: The Thomson Reuters Trust Principles.