LONDON, Feb 17 (Reuters) - Bank of England Deputy Governor Dave Ramsden said the central bank’s bond-buying programme remains its most immediate economic stimulus option and the BoE’s consideration of negative interest rates represented contingency planning. “My overall take on QE is still that it is a tried and tested tool,” Ramsden said in a speech on Wednesday to the University of Birmingham. “For me it is the marginal monetary policy tool at present.” (Reporting by William Schomberg and David Milliken)