British insurance giant Aviva has blamed summer floods in the UK for wiping out profitability in its general insurance lines.

Aviva's half-year results to December 31 reveal the company's combined ratio leapt six percentage points to 100% as profit in general insurance and health lines plunged 39% to £1.03 billion ($2.17 billion).

Aviva CEO Andrew Moss says the UK floods, which cost the company £475 million ($997 million), were the worst in 60 years and offset otherwise robust financial results.

The company's flagship general insurance business Norwich Union posted a profit of £433 million ($909 million), about a third of the £1.18 billion profit ($2.35 billion) in the prior corresponding period.

Net premium declined 3% to £5.4 billion ($11.3 billion).

Included among the results was a £48 million ($100.8 million) operating profit for Aviva's Australian life insurance business.