But RSA said its performance in emerging markets – including Latin America, Asia and the Middle East – is a cause for optimism.
Net premiums from developing countries hit £887m for the first nine months of 2012, up 15 per cent at constant exchange rates.
“Our unique geographic footprint gives us exposure to some of the most attractive insurance markets in the world,” said chief executive Simon Lee.
He admitted the UK market remains “challenging” but said “we have delivered growth across all business lines except motor”.
Worldwide premiums rose by four per cent to hit £6.2bn, with year-end investment income expected to be £500m.
The group’s combined operating ratio – a measure of underwriting profit that compares total premiums against total costs – is expected to be a healthy 96 per cent at the end of the year.
But Kevin Ryan, an analyst at Investec, said the firm’s stock is already fully valued: “A mixture of competitive insurance rates and poorly-performing economies means that RSA will continue to struggle to grow its top line.”