As you're new to FT, you may find better results posting this on the Virgin or BA fora where those who know the ins and outs of these programs can offer a better answer. However, I seriously doubt there will be a way to do this without losing most of the value of these miles. Some airlines provide for a transfer of their miles into HHonors, and from there you can convert your HHonors points into airline miles. But the value loss will be considerable. As an aside, given the "love" between these two UK-based competitors, your desire might be considered rather audacious, to say the least.