The collective shock and grief felt by Londoners following Thursday's attacks is due in part to our loss of invincibility', according to a counselling expert at Middlesex University.

David Griffin, a course leader in counselling, said that we have grown to believe that threats of this scale will not affect us.

"Many of us believed we were invincible, that crises and dramas of this scale happened elsewhere in the world. That belief has gone. We're vulnerable now. That's why many of us are struggling to use public transport or head into the city now. It's a form of shock, and a manifestation of grief."

Professor Griffin also said that the surprise nature of the attacks could be a reason why many of us felt numb after hearing the news.

"If we were told there was going to be an attack next Wednesday, we could mentally adjust. But it's the surprise nature of these attacks that results in many of us becoming numb. Many of my students were numb following the news. It's a coping mechanism, the first stage before the body adjusts and goes into shock.

"These things impact on our lives, our work and how we interact with people. We can still relate to the people involved and feel grief even if we didn't know them, as they were just going about their everyday lives."

Already people from this borough, and all London boroughs, are using the Tube and bus to travel into work. But it may take a while before we return to normal, said Prof Griffin.

"It's very hard to put a time limit on grief as it's such an individual and personal process. We have to come to terms with what we have lost," he said.