You can use the HM Revenue & Customs customs hotline to report all kinds of smuggling of goods - and particularly of drugs, illegal alcohol or tobacco.
Please do not use this hotline to report immigration matters.
Calls from landlines in the United Kingdom are free. You will not need to give your name or personal details when you call.
Phone:  0800 59 5000
Email:  customs.hotline@hmrc.gsi.gov.uk