"The same way stocks in the Milanka index (an index of liquid stocks in Colombo) will be traded in London."
Weerasinghe is head of Sri Lanka based MilleniumIT, which has built LSE trading system and is now owned by the exchange.
Weerasinghe said the LSE system was the fastest in the world and it has helped the exchange win back business and have around 70 percent of the British trading volume.
In March, Weerasinghe told a forum in Madrid that LSE was in talks with at least five other exchanges to open trading windows with London and they may become operational by July or August.
Weerasinghe said the international board will give a less costly way for participants in the London Stock Exchange to access Sri Lankan stocks and the company's firms will be able to access LSE liquidity at a far cheaper way compared to getting a dual listing.
Weerasinghe said a recent central bank decision to allow Sri Lankans to invest up to 200,000 US dollar abroad will also give them an opportunity to also trade in stock from London.
Responding to a query from Sri Lankan regulators, Weerasinghe said firms in the international board as well as its transactions will continue to be governed by the rules of the home country.
He said there was a demand for the mechanism from investors who wanted round the clock trading.
He said Sri Lanka could also offer the service to investors in the South Asian region especially to Indians, who were now allowed to invest up to 300,000 dollars a year abroad.
"This will give us an opportunity," he said.
He warned that other country's will seize the chance and Sri Lanka may miss the bus. Firms as far as Malaysia had raised capital in Colombo before independence from British rule when the country had a currency board or hard peg to the Sterling allowing free movement of capital and economic stability.
But a central bank was set up in 1951, which printed money to finance deficits, breaking the peg, and draconian exchange controls followed within two years. Sri Lanka also suffered high inflation and frequent balance of payments crises.
Hong Kong, an Asian financial centre has an orthodox currency board. Singapore now has a modified one.