Sir Charlie Mayfield had said that the government needs to do justice to the complexity surrounding the UK’s withdrawal from the European Union.

The John Lewis Partnership chairman told Retail Week: “We recognise that the issues related to leaving the European Union are extremely complicated but we do want to see justice being done to that complexity.

“There needs to be a serious parliamentary debate to find the best way forward for the country and economy.

“I think it is really a matter of making sure that we can make some broad decisions about the basis on which we will be leaving the European Union, and I think that’s where it requires serious parliamentary debate.”

Mayfield was speaking on the day of John Lewis’ interim results, which saw pre-tax profits crash 53% despite a modest rise in sales.

Pre-tax profits excluding exceptionals across the partnership were down just 4.6% to £83m, but they crashed 53% to £26m including exceptional items and property profits. 

Across the partnership, total sales rose 2.3% to £5.39bn. Sales at Waitrose and John Lewis rose by the same proportion to £3.34bn and £2.07bn respectively.

Like-for-like sales were up 0.7% at Waitrose and 0.1% at John Lewis.

Mayfield warned that while sales growth had continued in the first weeks of the second half, John Lewis expected the headwinds that had dampened consumer demand and put pressure on margins to continue into the next year.

He explained that those factors, as well as higher pensions accounting charges due to low interest rates, would affect full-year profits.