One in four small U.K. exporters have halted sales to the European Union because of red tape caused by Brexit, according to a survey published Monday.

The polling by the Federation of Small Businesses will add to concern that leaving the EU is further damaging the pandemic-hit economy by reducing trade and increasing costs. Official figures show exports and imports fell sharply after Britain completed its withdrawal from the bloc on Dec. 31.

“Three months on from the end of the transition period, what we hoped would prove to be teething problems are in danger of becoming permanent, systemic ones,” said FSB National Chairman Mike Cherry. “While larger firms have the resources and bandwidth to overcome them regardless, smaller traders are struggling, and considering whether exports are worth the effort anymore.”

The survey found that 23% of exporters have temporarily halted sales to EU customers and a further 4% have decided to stop selling into the bloc permanently after new trading rules took effect from the start of the year.

The vast majority of those doing business with Europe have been hit by shipment delays or loss of goods, and many are considering establishing a presence in an EU country to ease their exporting process, according to the survey of almost 1,500 firms.