Efforts to demolish a mill ravaged by flames have been delayed – because of 3,000 bales of wool still inside.

Demolition workers spent all of yesterday moving charred remnants of bales out of the still-smouldering wreck of Jack Walker & Son’s premises in Listerhills Road.

But the mammoth task took longer than expected and is likely to go on for most of today, according to demolition contractor Thomas Crompton.

A 60-ton excavator, the biggest machine of its kind in Yorkshire, was brought in to shift the 4,000 tons of debris.

Heavy-weight steel girders, some twisted from the intense heat of Wednesday’s blaze, were piled high alongside cast iron columns which will be now be traded in as scrap. The wool, once out, will be taken for landfill while bricks and stone will be crushed to sell on as hardcore.

Firefighters were on site as the mill walls came crashing to the ground in case the fire ignited again.

Bradford crew manager Paul Broadfoot said the fire had been made more fierce by lanolin that had soaked into the mill’s floorboards over the years.

He said: “The lanolin would have made what was a bad fire, even worse. Bales of wool would have been on some of the upper floors but they have ended up in the basement – that’s what is still causing lots of smoke.”

Police are still searching for clues with fire investigators to find out what started the massive blaze which was tackled by ten pumps at its peak as flames shot almost 20ft into the air.

The investigation is examining CCTV footage and a silver car found at the scene.

Detectives want to find out how the car, burned out at the same time as the mill, came to be there and whether or not it was responsible for the inferno.

Police removed it before yesterday’s demolition began.

As the excavators worked their way through the rubble, there was no sign at the scene of the owners Jack Walker and his son Philip who are too upset to speak about the fire.

One of the demolition workers said Mr Walker senior had visited the site earlier in tears to take photos of all that remained of the business that he said he had built up over 54 years.

Anyone who saw anything suspicious on Wednesday night should call police on 0845 6060606.

e-mail: kathie.griffiths @telegraphandargus.co.uk