Taken from Motor Transport website
UK hauliers will no longer need ECMT permits to access the EU in the event of a no deal Brexit, after a provisional deal between the European parliament and member states this week. However the agreement will only run for nine months after Brexit, can be unilaterally revoked by the EU and UK hauliers’ cabotage rights will severely limited and progressively reduced over the nine month period.
Full article here: EU to "significantly" limit UK haulier cabotage rights under no deal Brexit but rules out need for ECMT permit | Article | Motor Transport