With commodity prices in full retreat, the strong weighting of oils and miners in the Footsie index means the top share index is set to open sharply lower. City traders expect the blue-chip index to kick off more than 50 points lower.RSA Insurance hailed a strong start to the year with net written premiums of £2.1bn in the first quarter, up 8% on a year earlier. All regions delivered good growth. The group remains confident of delivering full year premium growth of around 10% in International, targeted growth in the UK and double digit growth in Emerging Markets.Telecoms giant BT saw underlying profit before tax surge 21% in the final quarter of its financial year (Q1 2011) from a year earlier, despite revenue easing 6% year on year. The full year dividend has been hiked 7% to 7.4p. Oil and gas firm Tullow said it has performed very strongly so far in 2011, with "excellent results" from its drilling programme in Ghana, while significant progress has been made in Uganda.