Trading on the LSE’s electronic platform was shut down this morning on one of its busiest days of the year.

The timing of the shutdown is unfortunate for the LSE, which is facing increased competition from rival trading platforms such as Turquoise, a Europe-wide platform set up by a number of the world’s biggest investment banks.

Another rival, Chi-X, claims to have taken over 15 percent of trading in FTSE 100 stocks recently.

To counteract the challenge, the LSE slashed trading fees at the start of this month in response to a partial launch of Turquoise, which is not due to start trading proper until October.

Today’s debacle was thought by the BBC’s Business Editor Robert Peston, to have serious consequences for the exchange. A great deal of money was tied up in the system, money that could not be used in a rapidly rising market.