On Wednesday, the LSE suspended trading in a small handful of stocks due to a technical glitch in part of its market data feed.

The breakdown led to a flurry of e-mails to trading desks across London from competing execution venues that remained open for trading in the affected stocks.

However, in a re-run of events last year when the LSE's TradElect system was hit by connectivity problems for a whole day, the expected fragmentation failed to materialise.

"London traders simply munched on their bacon rolls until the LSE fixed the problem a few hours later," says Steve Grob, director of strategy at Fidessa, who points out that the average FFI of the stocks in question (2.25) was, in fact, slightly lower on Wednesday than it had been for the previous week (2.3).

"There appear to be three reasons for this," says Grob. "Firstly, the primaries are responsible for maintaining an orderly market in the stocks they list and so traders are reluctant to trade a stock without its "parent exchange" being open. Secondly, a lot of liquidity providers use the primary market price as the starting point for their calculations - without this they simply can't make markets in those stocks. Finally, there is the psychology of the market that still feels that stocks "belong" to particular markets."

While Thomson Reuters and others have sought to introduce consolidated feeds displaying prices across multiple execution venues in Europe, Grob feels that individual efforts will fail to have an impact unless they are fully supported and mandated by the industry.

"My suggestion is that we all get together to define this and fix the problem - otherwise we may find the regulators doing it for us," he says.