Software and outsourcing specialist Northgate is getting back on its feet after its Hemel Hempstead headquarters was almost destroyed in the recent Buncefield oil depot fire.

Massive explosions destroyed much of Northgate's infrastructure on Sunday, and injured three employees.

The force of the blast heavily damaged the building, blackening and collapsing one side and leaving debris strewn around the site. Inside, computer systems that provide payroll and human resource services for private companies, servers hosting websites and hosted services for local governments, police, fire and health services were destroyed.

Northgate provides IT services to about 90 percent of local UK governmental entities and police forces. Other major clients include Tesco, the Labour Party and Manchester United.

The 150,000-square-foot building sustained "several million pounds" worth of damage, CEO Chris Stone said, and about 20 percent of Northgate's operations were affected.

However, data losses appear to be minimal. As part of its normal procedures, data was recorded to tape and picked up from the headquarters building every day at 7am and taken to a Northgate storage facility.

The tapes from Saturday were ready to be picked up when the accident occurred. Data from Sunday was also destroyed.

The data, which may have included information from five hospitals that Northgate provides hosted patient administration services to, will have to be recompiled. Some hospitals keep written records while others store electronic data locally, officials said. That data is later collected and held by Northgate.

The company has set up new hardware systems at its 25 facilities throughout the UK to replace the destroyed ones. Northgate also has contracts with third parties to provide server storage. Northgate said it has nearly completed setting up replacement hardware.

The force of the explosion was so strong that a buried back-up generator with its own fuel supply was ripped out of the ground, Stone said in the BBC interview.

Since the headquarters will be unavailable for at least a year, Northgate has moved its operations to it central London office.