A senior banker at a leading British lender has become the first person to plead guilty to UK charges linked to a global inquiry into the alleged rigging of benchmark Libor interest rates, a scandal that has shredded faith in financial services. The banker, who cannot be named for legal reasons, pleaded guilty last Friday, providing a timely boost for Britain’s Serious Fraud Office (SFO), whose independence has again come into question three years after it narrowly avoided being rolled into an FBI-style body by Home (Interior) Secretary Theresa May.