Barclays must raise its returns and that means making its investment banking arm Barclays Capital a more efficient user of capital. It needs more profit if it's to have flexibility in its Basel III capital while also sustaining growth and sidestepping a capital raise. Simple really.

In a recent presentation, Barclays CFO Chris Lucas outlined a couple of scenarios for the next three years which saw the bank's core Tier 1 capital ratio rise to 11.5% by the end of 2013 with no organic growth in risk-weighted assets or remain at the current 10% if it grows assets by £75bn. Those scenarios are based on its estimate that it will have £505bn of risk-weighted assets after Basel effects and on consensus estimates of its net income.