It was a good day and then a bad day for BT yesterday. First, the telecoms giant announced the rollout of its next batch of superfast broadband exchanges and then, one of its existing exchanges was hit by a flood, knocking out part of London, with a knock-on effect on other exchanges. Firefighters were at the exchange from 7,30 this morning, dealing with the incident.

Users of voice, broadband and mobile services have been affected by the outage. According to a Press Association report, Barclays Bank has been badly hit. A bank spokesman said  three central London branches - Marylebone, Portman Square and Sloane Square - had been closed all day following the incident, adding that "The branch network relies on telephone links to be able to operate and without connection to the telephone network there was no alternative but to close and redistribute staff to other branches."

Many other businesses in the north-west of London have also been affected. BT admitted that "tens of thousands" of customers had been affected by the flood.

BT put out a statement saying that it could not say when the exchange would be back to normal. It's not yet known how the flood started; there are some reports that a worker drilled through a pipe but nothing has yet to be confirmed.