Fuel pumps at a service station frequented by the black cab trade were sealed off with 'crime scene' tape this week after a visit from HM Revenue & Customs.
An HMRC road fuel testing unit visited Acres service station underneath Harling House on Great Suffolk Street on Wednesday.
The closure of the Acres service station came on the same day that eight men were arrested as part of an HMRC investigation into a suspected £3 million fuel laundering fraud. An HMRC spokeswoman would not say whether the Great Suffolk Street garage was linked to this investigation.
"Laundering fuel is a serious crime, which HMRC is determined to tackle," said John Cooper, assistant director of the fraud investigation service at HMRC.
"Around £100 million in unpaid duty and taxes is lost each year to fuel fraud in the UK, money that should be helping fund public services. We are determined to take that profit away.
"The toxic waste from fuel laundering poses a real threat to the environment and costs thousands of pounds to dispose of safely. Taxpayers are not only missing out on the stolen tax, but we also have to fund the substantial clean up and disposal costs.
"We urge anyone with information about the transport, storage or sale of suspected illicit fuel to contact our fraud hotline on 0800 788 887."
Other businesses serving the cab trade in the yard behind Harling House are not affected by the HMRC operation.