London market insurer Markel International has maintained underwriting losses in the first half of 2011, despite an improvement in gross written premiums.

In the six months to June 30, GWP rose 22% to $482.7m, compared to $395.3m for the same period of 2010.

Markel reported the increase was primarily due to an increase in premiums from its Canadian operation, Elliot Special Risks, as well as an improved pricing environment and organic growth at its marine and energy division.

Combined ratio was 130% for the six months ended June 30, 2011 compared to 112% for the same period of 2010. The COR included $84.0 million, or 25 points, of underwriting loss related to the US storms, Australian floods, New Zealand earthquake and Japanese earthquake and subsequent tsunami.

Markel chairman and CEO Alan Kirshner, Chairman and Chief Executive Officer, attributed the weaken results to first half weather-related catastrophe losses. “While operating at an underwriting loss is disappointing, we continue to take the necessary steps to maintain long-term underwriting profitability and are pleased with our growth in operating revenues,” he added.

Markel Corporation reported a diluted net income per share of $3.95 for the six months ended June 30, down 40% on the same period in 2010.