BBC News Published image copyrightPA Media A Northern Ireland port operator has questioned whether businesses in Great Britain will be prepared for the end of Irish Sea trade border "grace periods". MLAs have been told how ports in NI are benefiting from extra freight traffic which is no longer travelling through Dublin because of checks. The first of the grace periods ends at the start of April. NI's four port operators gave evidence to Stormont's Infrastructure Committee about the effect of the NI Protocol. The grace periods were agreed by the UK and EU to allow businesses in NI to adapt to new rules on customs and product standards which came into force on 1 January.