Was the London "Power Surge" An Incident Code?

Immediately after the first reports of a subway explosion in London, Associated Press moved the following wire story lead:

Power surge causes explosion on a subway line in London's financial district
01:45 AM EDT Jul 11

LONDON (AP) - An explosion on a subway line Thursday morning in London's financial district injured several people, British Transport Police said.

Metronet, a company which maintains the subway infrastructure, said the explosion was caused by a power surge. London Underground reported a second incident at another subway station in northeast London, but gave no details immediately. London Ambulance Service said several vehicles had been dispatched to the area near Liverpool Street station.

Apparently world media, including BBC, Reuters, and CBC, did similar.

While it's obvious that the media were reporting what they had been told were the facts, there remains the question whether authorities made this original statement out of confusion or, as has been suggested, to avoid panic and buy extra time for emergency plans to be activated.

A typical account on Scotsman.com suggests the latter:

That London was under attack was confirmed within seconds.

[...]

Media organisations were demanding to know what was going on. A holding answer was given: all the fuses on the lines had been blown, providing evidence that there had been a "power surge". Experts believe the claim about a power surge gave London's emergency planners a crucial few minutes to set up their action plan. It may have achieved this, but it also meant that, across the city, few were aware that terrorists were striking London - and the last bomb had not yet detonated.

In a later "opinion" column on this same site, writer Fraser Nelson comes up with an even more interesting report, suggesting that the "power surge" might actually have been an incident code, that was promulgated through the media to get out the word:

LONDON'S emergency services had practised the drill several times over - "power surge" is the euphemism for a terrorist attack and the early reports of such a surge carried enough weight to reach the Prime Minister that morning. By 10am, three other explosions had followed and he was informed of the worst. Again, he walked out of the meeting and into Gleneagles' grounds, this time to absorb the scale of the tragedy unfolding. In London, ministers were already meeting in Cabinet Office meeting room A. They swung into the well-rehearsed plan.

In any event, the terrorists have done it again. Innocent people are dead, and the only real power surge belongs to bush and Blair, two despicable leaders who feed on these attacks and grow stronger from every one. While it's unlikely that terrorists really are, as has been so quaintly asserted, merely people who "hate our freedom," the result is the same. More bodies, more fear, less freedom.

My major fear is for the social experiment called democracy, and its long term survival. The prognosis has to remain grave.