John Varley, chief executive of Barclays, attacked Barack Obama on Tuesday for taking “unilateral” action to curb banks’ riskier trading activities. Mr Varley said the US president’s proposals proposals flew in the face of efforts to forge an international consensus on financial reform. The first UK bank chief to testify before a parliamentary committee looking at reforms of the banking system, defended large, integrated institutions such as Barclays, telling MPs that capping banks’ sizes would not prevent another financial crisis.