Insurer Lancashire Holdings posted a rise in half-year profits as it saw strong overall premium growth in the last quarter.Pre-tax profit for the six months rose to $148.2m from $136.2m. Gross written premiums was flat at $384m but in the second quarter it rose 23% to $241.9m. Net written premiums came in at $337.9m against $324.3m.The group said it has been somewhat surprised by the reduced demand this year for Gulf of Mexico energy hurricane cover, which reduced the level of business written in that particular class compared to expectations. At the same time though, it has made progress in building its property catastrophe book in many United States' critical catastrophe zones."Despite reduced premium income in the Gulf of Mexico market, the Group has seen strong overall premium growth in the quarter. We are also pleased with the business written in July at rating levels supporting our decision to hold back capacity earlier in the year," said the group.Interim dividend was 5 cents per common share.