An investigation into the cause of a blaze that ripped through a Watton business could begin later today (Tuesday) after serious structural damage stopped fire officers starting earlier.

The home of carbon fibre and reinforced plastics company Carbonelite on the Norwich Road Industrial Estate was gutted after fire broke out in the early hours of Saturday.

Fifteen firefighter crews from across Norfolk attended and spent more than five hours battling with the blaze, having to contend with high winds and flying debris. They prevented the fire from spreading, but some neighbouring units suffered heat and smoke damage.

Nationwide Food Packing next door could not open yesterday, and its 12 staff were told to stay at home. The business, which packs vegetable bouillon for customers worldwide, had a lucky escape, but large cracks have appeared in some walls.

Owner Brenda Henderson, who spent yesterday clearing up, said staff usually packed up to 26,000 tubs of bouillon granules a day.

'It's an absolute nightmare,' she added. 'This is usually our busy time of year. I don't know when we can start work again: I'm waiting to hear if it's safe. The fire went in an L-shape around us.'

Mrs Henderson, who also employs her son and partner, said Carbonelite founder Dave Greenwood had been devastated when he visited the site on Saturday.

Investigations into the fire have been hampered by the sheer scale of the damage.

Norfolk Fire and Rescue Service said last night that the site remained unsafe and that investigations would be delayed until at least today.

As well as producing carbon fibre wings for racing cars, Carbonelite has worked on large-scale sculptures. It helped, too, to design the seven-storey stage for the Rolling Stones' Bigger Bang tour in 2005, constructing it within eight weeks of being shown a rough sketch.