Meat and dairy products, plants and seeds are among the goods now subject to physical checks when imported to Britain from the European Union.
Businesses have warned the trade checks, which will see import costs increase immediately, are expected to hit smaller companies hardest and lead to price rises being passed on to customers for certain products.
The second phase of border controls kicked in from midnight and have been introduced as part of the UK’s Brexit trade agreement.
The government said its new border model would “improve our biosecurity”, adding the costs for businesses would be “negligible compared to the impact of a major outbreak of a plant or animal disease”, such as foot and mouth.
The UK officially left the EU four years ago, but it has taken some time for the new trade rules to be implemented – legally required under the Brexit agreement – for goods travelling from the bloc to the British Isles.
Health certificates were introduced in January on EU goods ranging from cut flowers, to fresh produce including meat, fruit and vegetables, but on Tuesday, physical checks for the goods have come into force.
British exporters trading in the other direction have already faced increased red tape for three years. The introduction of such UK border controls is reversing the free flow of such goods, which had been allowed under the EU single market since 1993.
The physical checks will be carried out based on the “risk” category that goods fall into. For example, the government said high-risk goods, such as live animals, will be subject to identity and physical checks for pests and diseases at the border.
Products that present a medium risk to biosecurity will also be checked, while low-risk goods, such as canned meat will not require any checks.
The new checks are not yet being applied to goods from the Republic of Ireland, which is a major supplier of food to the UK.
The UK government says the checks on Irish goods will not happen before November.