It is just a short distance from some of the UK's most prestigious areas and has been called "the most expensive street in the world " and "Billionaire's Row". Home to more than 60 enormous mansions, worth a combined hundreds of millions of pounds at the very least, The Bishops Avenue has an extraordinary history which includes pop stars, royal families, tyrannical regimes and murder. But while many of the palatial homes on this London street are still lived in, others lie empty and seemingly