Heart-stopping video of a toddler walking calmly along a window ledge on the ninth floor of a building has left viewers shocked that the incident did not end in tragedy.

The child, aged between three and four, was filmed on Tuesday at about 6pm by a worker watching from an office located in front of the residential building in Goiania, central west Brazil.

The woman, who preferred not to be named, recounted how she saw the little imp climb out of the bedroom window and saunter confidently up and down the windowsill, to the balcony and back, as if it was the 'most normal thing to do'.

The tot's 30m-high (around 100ft) antics continued for about 10 minutes until an adult appeared on the balcony and took him down with a scolding.

But even after being reprimanded, the little rascal appeared again outside the window minutes later, while another child inside the room tried to climb out to copy what the older sibling was doing.

However, on this occasion the mother was quick to react and took her son down once again.

The terrified worker said to Anhanguera TV: 'I was beside myself with worry and will never forget the panic I felt watching this scene unfold before my eyes.

'It's hard to see with the naked eye, but I realised the window has got a protective security screen over it and this acted as a safety net.

'But the boy treated the window sill as if it was a play area and slid the window frame back and forth as part of his game. Although the security mesh was there, it could easily have pulled away from the wall and I can't bear to think what would have happened next.'

In desperation, the office worker asked a colleague to run to the building to alert the caretaker and residents in the apartment.

She is heard saying on the video: 'Someone has gone over there to warn the porter and to ask him to call the flat where the child is. My heart is beating so fast with the desperation.'

The caretaker was unable, however, to get hold of anyone in the flat.

The concerned eye-witness said: 'I was watching all the time and I must have held my breath for the duration the child was on the window's edge. He must have thought he was Spiderman.

'And I couldn't believe how calm the mum was when she saw him do it again. It was as if it was a routine stunt and she was used to it. She clearly told him off but that didn't seem to make much of a difference.'

Lieutenant colonel Fernando Caramaschi of Goiana fire department who watched the footage said: 'The screen is a piece of security equipment which is there for protection to stop birds entering into the room and to prevent someone from falling out of the window, but it may not always hold under a certain level of stress.

'Every screen has a valid by date and the warranty expires after about five years. Rain and sunshine also affect its integrity and lifetime.

'All parents in high rise flats should be checking their screens frequently to see if the screws are still holding strong and not rotting due to the weather, and the mesh is not weakening under environmental factors,' he said, adding that regular maintenance should be done by a reputable company to ensure the screen continues to meet safety standards.

Read more on dailymail.co.uk.