A baby boy who was hit by a falling lamppost remains in a critical condition, police said today.

The one-year-old was taken by air ambulance to the Royal London Hospital after the incident outside Chiswick town hall, just after 10.30am yesterday.

Passersby said the 32ft lamppost fell on to a push chair, crushing the tot inside. A female carer who had been pushing the pram escaped injury.

The baby boy suffered "life-threatening" injuries and is still in a critical but stable condition, police said this morning.

An unrelated 62-year-old woman, who was pinned under the lamppost, was taken to Charing Cross Hospital with suspected spinal injuries.

Posting on a community website, Colin Wren wrote: "The 62-year-old woman also involved in this shocking incident is my mother-in-law and has thankfully just left the hospital.

"She was with my un-harmed two year old daughter at the time the lamp-post struck her, so it could have been substantially worse.

"After having a series of X-rays and scans she miraculously only has bruises to her back, but I don’t think she’s going to get over what happened too quickly.

"She said that unfortunately the poor little fella was still in a critical condition."

An inquiry was under way today to find out whether construction work may have caused the lamppost to fall.

Health and Safety Executive inspectors have visited the site by Turnham Green, where building works have been carried out in recent weeks.

It was reported today that investigators believe the post's base could have been weakened by heavy machinery used to dig up the footpath.

Four contractors are thought to have been working on the site, including a utility company and one improving the road layout, the Evening Standard said.

One mum, who saw the incident unfold, has spoken of how she tried to help.

The passerby, who asked not to be named, said: "Unfortunately we saw the accident happen and called 999.

"A pole fell, hitting a baby buggy and a woman.

"The woman was on the ground but consious, and the baby was unconcious but breathing.

"I believe it was the nanny with the baby and the woman who was hit was unrelated.

"The ambulance and air helicopter were there very quickly and the boy was moved into the ambulance.

"Nothing hit the pole causing it to fall, so I have no idea what happend for it to fall.

"Very scary considering the number of people who use that crossing every day.

"I feel terribly for the people involved, and pray that they are ok."

It is believed the nanny was taking the baby to a "music time for under fives" class, one of many parent-and-toddler sessions held at the town hall.

Witness Nora Correa, 45, said: "Paramedics and police had the baby out of the pram and gave him mouth-to-mouth resuscitation on the steps of the town hall.

"He was pale and had his eyes closed. At first he wasn’t breathing but after a few minutes he began to move a little.

"The force of the crush had snapped the front two wheels of the pram off."

Another passerby said: "It was horrific."

One said the pram had "broken in two".

Nearby residents said street lights close to the town hall had been out of action the night before the incident. They questioned whether workers had repaired them early yesterday.

Others spoke of their concerns over safety on a community website.

A dad, whose child also attends the Chiswick Gymboree - which it is believed the injured youngster had been about to attend - told how he believed the injured baby may have been his own child.

"By some freak incident she wasn't at the class yesterday," he said.

"There was a moment when I thought it was my child.

"You go through complete anxiety. We all had difficulty sleeping thinking about the poor people and what their injuries were.

"In this day and age clearly this shouldn't have happened.

"Our nanny saw the work going on there and said she thought it looked dangerous."

He added: "We need to find out who is responsible and make sure they are held to account.

"My reaction is two-fold.

"On the one hand I am very concerned for the family involved but secondly I am outright angry that this could happen.

"It could have happened to anybody."

Yesterday afternoon Hounslow Council leader Peter Thompson, who is also Turnham Green councillor, visited the scene.

The road was open as usual today.

A spokesman for the HSE said: “We are involved in a joint investigation with police and our inspectors have been on site.”

A Hounslow Council spokeswoman said yesterday that the authority had been carrying out improvement works, which included changing several bus routes and providing improved pedestrian crossings, at the site.

She said no contractors were on site at the time of the incident.

She said: "This is an awful tragedy and our heartfelt sympathies go out to the injured and all their families.

"The council is cooperating fully with the police and health and safety executive investigations."

• Did you see what happened? Or do you know the family? Let us know by email (gholt@london.newsquest.co.uk), phone the newsdesk on 020 8744 4271 or leave a comment below.