LONDON (Reuters) - There has to be a breakthrough this week on a post-Brexit trade agreement, British and Irish ministers said on Sunday, as London’s top negotiator went back into talks saying progress had been made in recent days.Without a deal, around $1 trillion worth of trade would be at risk of disruption through tariffs and tougher rules after the Dec. 31 expiry of Britain’s transition period for leaving the European Union. That would deliver a fresh economic shock just as Britain and the EU are struggling to contain the economic fallout from the COVID-19 pandemic. “This needs to be a week when things move, when we break through some of these difficult issues and get a resolution and at least have some sort of headlines, if you like, of an agreement,” British environment secretary George Eustice told Sky News on Sunday. Irish foreign minister Simon Coveney said time was running out for a deal.