The exchange this month processed a record £17.62bn of transactions in one day on Tradelect, which went live in June, exceeding the previous high of £17.16bn.
The figures are significantly higher than the previous record of £13.4bn - set on 28 February, before Tradelect went live - and they will be seen as a vindication of the new technology platform.
The system, a complex piece of in-house-developed middleware, reduces the time taken to complete a share trade to 10 milliseconds and allows 3,000 trades per second.
"Before Tradelect, demand to trade shares would trail off because the system did not have the capacity to execute orders straight away," said a London Stock Exchange spokesman.
Recent volatility in the market has increased the volume of trades said Bob McDowall, senior analyst at TowerGroup. "If it had not had Tradelect, the exchange would not have been able to cope with these volumes, but it is now electronically geared up for this," he said.
The increase in business comes as the London Stock Exchange prepares for increased competition from rival exchanges.
Project Turquoise, which was set up by seven of the world's largest investment banks as an alternative to local European stock exchanges, will compete with the London Stock Exchange for stock trading business, which accounts for £164m, or 47% of the exchange's revenue.
Further competition will come from Plus Markets, which was granted investment exchange status last month, enabling it to trade in more markets.
Project Boat, which has been developed on the back of the Markets in Financial Instruments Directive by a consortium of major banks, will compete with the London exchange on the sale of market information, which creates 30% of the London Stock Exchange's revenue - worth about £106m last year.
The exchange is meeting this challenge with Infolect, a system based on Microsoft .net and SQL Server 2000, which recieves data directly from Tradelect to generate and sell market information.