Is the British prime minister, Boris Johnson, embarrassed or envious that a fellow Conservative, Sir Geoffrey Cox earned more than £800,000 for his expertise as a barrister as well as his £82,000 annual salary as an MP?  Sir Geoffrey, Boris and another Conservative MP, Owen Paterson, three prominent Brexiteers, all have form generating significant income streams in parallel to their public lives as prominent politicians.   But Mr Paterson’s fondness for a pay slip in one hand and a second pay slip in the other has landed all three in trouble.   In recent days Boris found himself desperately unsure whether to ditch his fellow travellers or throw…