The Liverpool Echo reported on 29th October that a man was arrested as he attempted to carry a bag stuffed with £10,000 in cash into Liverpool, the 42-year-old had just arrived on a ferry from the Isle of Man when police sniffer dogs brought him to the attention of officers. The suitcase he was carrying was searched, leading to the discovery of the money. It is not commonly known (despite posters at the airport and seaport) that one has to declare large sums of cash (€10,000 or more) carried or sent to or from the Isle of Man – including to and from the UK – and that the rules on declaring cash taken in and out of the EU also apply to cash moved between the UK and the Isle of Man (and the Channel Islands).
https://www.liverpoolecho.co.uk/news/local-news/ferry-passenger-tried-walk-liverpool-15345221