Sir Allen Stanford, the Texan billionaire, pleaded not guilty on Thursday to 21 criminal charges, including running a $7bn (€5bn, £4.3bn) Ponzi scheme and buying the co-operation of a senior Caribbean regulator.

The flamboyant businessman – whose lavish lifestyle helped clients believe that his business was booming – sat up straight in a courtroom packed with family and friends, giving occasional small smiles and nods to different people.