Anyone who was in London on July 7, 2005, has memories of that day. A year later, it remains etched in the national psyche and there were huge emotional after-effects, says Kate Nowlan, a trauma specialist who was called in by organisations to help their staff.

“There was a state of hyper-vigilance for about ten days afterwards,” she says. “People avoided public transport and walked or cycled to work and were more wary of each other. But, as winter set in, they got back on the buses and Tube and are not so vigilant now.

“It was noticeable that younger people were far more shocked than those who had lived through the IRA atrocities, and also that while Londoners had no choice but to return to normal, people from outside preferred to avoid London. That still affects business now.”

Malin Lund, a London PA who works at the PR firm Luchford APM, agrees that she was on edge for a while: “I was nervous after the bombings and more suspicious towards fellow passengers. But this feeling lasted no longer than a month.”

Transport for London says that passenger figures on the Underground fell immediately by 20 per cent. But by the end of July numbers began to rise, and had fully recovered by the last week in September. A spokeswoman said: “This is a demonstration of London’s defiance against terrorism.”

Kate’s company, CiC — Counselling in Companies — runs a 24-hour helpline with 650 counsellors nationwide. She says: “July 7 was a strange day for us. Usually the phones don’t stop ringing, but there was an eerie silence.” That evening, Kate was called to King’s Cross, to talk to staff of a building firm client that helped in rescue operations.

Such events leave their mark: “For the first ten days, people are in shock. It’s usually two or three weeks later that those who have been psychologically affected ring in.”

Symptoms include disruptions to appetite and sleep, palpitations and hypersensitivity such as jumping at the slightest noise. “Symptoms normally die down over a month, but anyone still experiencing them six weeks later needs help.”

Employers dusted off their business continuity and contingency plans, which many put into place after September 11, but had barely looked at since. Kate observes: “The problem with many plans is that they focus on disaster recovery for IT systems and not on people.” She advises employers to update and rehearse their plans regularly, and to communicate them, particularly to new staff.

One practical thing her organisation did after July 7 was to hold seminars on breaking bad news. There is, of course, no easy way to tell someone that a loved one hasn’t turned up for work or has died.

But there are simple things to consider, such as going with a colleague, so that one of you can stay with the person. “And never, ever say, ‘I know how you’re feeling’ – because you don’t.”

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