The accident landed Broadland (Builders) in court after the firm was subcontracted to install anchor bolts to secure the festive decorations.

Huntingdon Magistrates’ Court heard that on 29 November 2007 the decoration pulled out a large piece of masonry from near the top of the building housing the Norwich and Peterborough Building Society.

The decoration, fixing and masonry fell to the pavement below. A passing car was hit by the masonry and the metal frame.

Elena Giddens, 39 at the time of the incident and formerly of Eynesbury Manor in the town was knocked unconscious when masonry landed on her. She had five stitches to her head and suffered three broken ribs and a punctured lung.

Her friend, Anne Beck, then 35 and also of Eynesbury Manor, had been pushing her seven-month-old son, Myles, in his pram along the High Street.

She dived on top of the pram to protect Myles before she and Giddens pushed the pram away from the falling debris. She sustained three broken fingers and bruising to her arm, hand and back.

The Health and Safety Executive investigation found that the decoration, which weighed approximately 50kg and was suspended on two catenary wires, had been attached via an anchoring bolt that was fixed into an unsafe part of the building.

The mortar was also known to be weak, and no survey had been carried out.

At Huntingdon Magistrates’ Court, the director of Broadland (Builders) Limited, John Fifield, pleaded guilty to breaching safety laws.

The company whose registered address is Euro House, 1394 High Road, London, N20 9YZ, was fined £12,000 and ordered to pay £4250 costs.

HSE Inspector Paul Hoskins said: “Incidents like this are entirely preventable.

“Guidance on suitable and safe locations for this type of fixing is freely available from trade associations, and could easily have been referred to.

“Furthermore, had a suitable building survey been performed, it too could have highlighted the unsuitability of the chosen fixing location.

“Since the incident, the company involved has undertaken further staff training and is now a member of the relevant trade association.”