The series of three explosions at the 100-acre site, which occurred at 6am on Sunday 11 December, affected businesses in and around Maxted Road, Maylands Avenue and Boundary Way.

Print firm Colour Quest had staff working when the blast occurred on Sunday morning, although none were injured. The firm is now working remotely.

Managing director Tyrone Spence said: "We are not allowed to visit our site until the police give us the go-ahead."

Apex Digital Graphics, which is located 500m from the depot, had its windows blown in. The Apex management team are operating from home, and Morgana in Milton Keynes has offered temporary office space.

Pre-press software firm Colourbyte's premises suffered damage, with lighting, ceiling tiles and air conditioning units all being blown off.

Director Tim Stockley, whose home in Leverstock Green was also damaged by the force of the blast, said he had managed to retrieve paperwork, PCs and laptops and secure the firm's premises, prior to the police cordon being activated.

Xerox's document supplies office is closed, with all 160 staff either working from home or temporary offices. The company had been unable to gain access to its office to assess the level of damage.

Wide-format printer and proofer supplier Epson's offices are out of action and off-limits until further notice. Temporary offices had been secured in Uxbridge.