London Market Principle (LMP) slips are being used in 70% of transactions, according to the London Market Insurance Brokers Committee.
The findings show a 20% increase at 1 April 2003 from figures reported for 1 January 2003.
LMBC spokesman Mark Barwick said: "There is now a strong commitment right across the London Market to improve the quality of the LMP Slips to ensure that the key objective of the reforms programme, contract clarity, is achieved."
He added that the LMBC also plans to add information to the slips to increase clarity.
