Earlier, the Financial Times said plans presented by the European Commission on Monday suggested that Britain could be fined or lose preferential access to the European market if it violated the terms of a future relationship deal.

The spokesman also said the government would seek to overturn any changes brought to its divorce deal, or Withdrawal Agreement Bill, by the upper house of parliament, the House of Lords.

(Reporting by Kylie MacLellan, writing by Elizabeth Piper, editing by William James)