The BBC's Peter Gould: Police want more eyewitness accounts

Aiah Menjor, who works at the Iceland store where the nail bomb was left on Saturday, was injured by nails from the blast as he tried to clear people away from the scene.

Police are still sifting through recordings from nearby security cameras to see if the bomber was caught on video.

The door of a delivery van was blown off in the blast

Mr Menjor said: "Nobody took it seriously because people were saying to me 'oh man, look, we have never had this before and we don't expect a bomb to be here. This is not a bomb'.

"Even when I said 'move' they wouldn't move. They would say 'no, we don't expect this in Brixton so this is not a bomb'."

Mr Menjor is being treated at St Thomas's hospital, south London.

There are fears that he may lose the sight in his left eye.

Forensic scientists search for clues

Of the 48 people injured in the blast, 14 are still in hospital, with four giving doctors cause for concern.

Two men, being treated in King's College Hospital, may lose their sight.

A 16-year-old girl is being treated in St Thomas's hospital, where she was operated on for shrapnel injuries on Sunday.

A 23-month-old boy in the same hospital is in a stable condition after an operation to remove a four-inch nail from his skull.

Aiah Menjor describes the moment the bomb went off

Gary Shilling, 14, who removed the bag with the explosive away from the busy shopping area, was greeted with cheers as he returned to the bomb site to see his friends at the market before going to school.

The teenager, whose foot was pierced by a six-inch nail, said: "I'm fine, but my foot is knackered."

"It was terrifying. I found the bag and moved it out of innocent people's way, and seconds later there was just a huge bang."

Explosives expert Dave Thomson: "They are crude devices which are simple to put together."

Debris which had littered Brixton's Electric Avenue had been cleared away and little evidence remained of the blast.

The street remains cordoned off, but police say it will be reopened as soon as the shops which line both sides had been made secure. Many still have broken windows.

One market trader, who declined to be named, was among the few setting up fruit and vegetable stalls along Electric Avenue this morning.

No motive established

He said: "What we want is just to get back to normality. We just want things to be like they were before.

"You can't let this sort of thing beat you, can you?"

Detectives still examining possible motives for the bomb attack as they step up their hunt for the culprit.

No reason has been established for Saturday's attack

Police will begin interviewing scores of witnesses, hoping to confirm sightings of a suspicious "blond man" outside the Iceland supermarket where the bomb exploded.