More than 90 per cent of Barclays’ profits came from its investment banking arm in the first half of the year as a ￡1bn bill for mis-sold loan insurance hampered its efforts to build up the retail business.

Barclays Capital provided ￡2.4bn ($3.9bn) of the bank’s total ￡2.64bn pre-tax profit in the first six months despite challenging trading conditions.

First-half profits at the division were almost 30 per cent lower than a year before as revenue slipped at its core fixed income, currency and commodities division. But a provision in the retail business for payment protection insurance and a costly withdrawal from parts of its European branch network meant the investment banking division still accounted for a larger proportion of overall revenue than a year ago.