“Most” EU goods will be waved through dozens of British ports to avoid any traffic delays if Britain leaves without a deal on 29 March.
Should Theresa May not secure a formal divorce agreement with the union, British businesses importing from the EU should have all goods subject to rest of the world checks, meaning they would have to give a full declaration and pay duty before they come over the border.
But in a bid to avoid huge traffic jams and delays, HMRC has announced transitional plans which will be in place for a year, where EU goods will be waved through as they are now.
The simplified procedures will be in place for three to six months before HMRC reviews them.
Officials have promised to give a 12-month notice period to businesses for any changes made to the procedures within that time period.
No-deal Brexit means Britain will trade with the EU on World Trade Organisation terms (WTO) which regulate global trade, with rules on import taxes and limits on the number of goods supplied to other countries.
The plans are in place to avoid congestion, but critics say it means officials won’t know what is coming into Britain.
There are 21 locations which will allow EU products to come through without additional checks, including Liverpool, Portsmouth, Hull, the Channel Tunnel in Folkestone, Pembury and Tyne.
The simplified checks are available to businesses with an EORI number, which businesses were able to register for from December, who are based in the UK, and are importing from the EU into the UK.
Businesses importing controlled goods from the EU into the UK will have to complete a “simplified frontier declaration” before importing the goods, make sure they arrive with all supporting documentation and then send another supplementary declaration within a month of getting the goods.
Those importing standard goods will have to make a “customs declaration within your commercial records when the goods cross the border”.
The businesses will then have to make a supplementary declaration about a month after the goods are received.
Best For Britain said this would mean goods would arrive in Britain before importers have informed HMRC.
Labour MP Geraint Davies said: “They said we would take back control of our borders but now the plan is to wave things through irrespective of our safety.
“We’ll have no idea what is coming into our ports.”