In a High Court writ, IT security specialist Vogon International alleged the SFO has failed to pay a bill for more than £310,000 for tape processing work.
With interest added, Vogon is suing the SFO for a total of £333,866.36 and will be seeking continuing interest of £157.19 a day.
Vogon gave the SFO a quote for its work in August 2001 "to inspect and determine the configuration for each MS Exchange database" from tapes. Neal Astle of the SFO faxed a signed acceptance form.
Astle also indicated that the SFO wanted the work to be done quickly, which meant a price increase of 150%, according to the writ.
Shortly after Vogon had started work, Aiden Gilbert of the SFO telephoned to ask for a provisional estimate of fees, and when he was told £150,000, the gist of his reply was that he had expected Vogon's fees to be more than £150,000, the writ said. The estimate was later confirmed in an e-mail.
Vogon finished processing tapes for the SFO on 31 August 2001 and submitted an invoice for £314,375 plus VAT, to be paid within 28 days.
The SFO asked Vogon to issue a credit note and reissue the invoice, but raised no complaint or query. The reissued invoice should have been paid by 4 October last year, the writ said.
The SFO allegedly failed to pay the bill, which also included £1,500 for setting up and populating MS Exchange databases, and £1,250 for processing data from each database to produce one PST file per mailbox.
A spokeswoman for the SFO confirmed that Vogon had started proceedings but said that due to the ongoing nature of the litigation no further comment would be forthcoming.