A series of three explosions at the 100-acre site at 6am on 11 December damaged business premises in and around Maxted Road, Maylands Avenue and Boundary Way.

Among those firms worst affected were Colour Quest, situated less than half a mile from the blast, Apex Digital Graphics and pre-press software firm Colourbyte.

Others included Fujifilm's Electronic Imaging (FFEI) division's R&D facility, Xerox's document supplies office, and printer and proofer supplier Epson's offices.

Insurance assessors have said the cost of the damage is expected to run into millions of pounds and one assessor likened the damage to that of the 1987 storms.

Colour Quest had staff working when the blast occurred on Sunday morning, although none were injured. The firm's sales staff are now working remotely.

Managing director Tyrone Spence said he hoped to get a better idea of the extent of the damage once allowed on site.

"A police official said it was like World War three," he said.

Colourbyte director Tim Stockley said a meeting for local businesses and residents hadn't provided any clear indication as to when things would return to normal.

"The police and fire officials have said that once the fires have been put out and cooled down, people will be allowed back, but only once each premises have been checked.

Fujifilm Graphic Systems marketing manager Graham Leeson said he could not comment on the damage to FFEI's Electronic Imaging facility.

Extent of damage
- Apex Digital Graphics: Windows blown in. Management working from home.

- Colour Quest: Staff on site when blast happened, but all accounted for. Damage to building. Staff working remotely.

- Xeox Document Supplies: Office closed with all 160 staff either working from home or temporary offices.

- Epson (UK): Offices out of action. Temporary offices secured in Uxbridge.