Bank’s boss says chancellor must signal intentions clearly given risk to borrowing and mortgage rates

Rachel Reeves must “get the balance right” when announcing changes to Britain’s debt rules in next week’s budget given the potential knock-on effects to borrowing and mortgage rates, the boss of NatWest has warned.

The bank’s chief executive, Paul Thwaite, said markets would be sensitive to the chancellor’s reasons for releasing up to £50bn of borrowing headroom after she confirmed in Washington on Thursday that she planned to rewrite her fiscal rules.