LONDON (Reuters) - Britain and the European union are at an impasse over changes to the parts of the Brexit deal governing trade with Northern Ireland, Britain's Europe minister James Cleverly told a parliamentary committee on Thursday.

       "The truth is that we have come to something of an impasse, and I don't think that's through a lack of goodwill, and I think it's more through what we regard in the UK as an overly limited (EU) negotiating mandate," he said.

       Cleverly said he still hoped to reach a negotiated deal with the EU. He declined to comment on media reports that the government was preparing legislation that would unilaterally overrule parts of the Brexit deal.

       But, he did say that pressure to find a way forward was mounting and Prime Minister Boris Johnson had been clear on the need to look at ways to alleviate the tension caused by the current arrangements.

       (Reporting by William James. Editing by Andrew MacAskill and Kate Holton)