As the Commission says:
The government's actions in such cases are a prime example of the arbitrary exercise of state power. There is an account of what can happen here.
The UK's practices jeopardise the right of all EU consumers to buy goods in other member states, excise duty paid, and bring these products home for their "own use" without any formalities and without having to pay taxes a second time.
In particular, the commission considers the UK's policy of seizing goods and sometimes cars even for minor offences is disproportionate.
Of course, there are plenty of good cause in Britain which are none of the Commission's business. But if the European project is not about the free movement of goods within the Community then it is about nothing.
And, if anything can reconcile Tory voters to Europe it must be the project of more cheap drink and fags.