Osborne & Little, the luxury wallpaper chain owned by the family of former chancellor George Osborne, says it expects to benefit from the fall in the value of the pound triggered by the Brexit vote.

The company said there would be “limited impact” in the short term from Britain’s decision to leave the European Union, but if sterling remained weak, it would bring a “material benefit” to the business next year.

The comments, made in the company’s latest accounts, will make uncomfortable reading for Osborne, who delivered a series of dark predictions about the likely impact of Brexit on UK companies before the referendum in June.

He said departure from the EU would be a “most extraordinary self-inflicted wound”, would leave Britain “permanently poorer”, and plunge the country into immediate recession, requiring emergency budget measures.

The Osborne & Little board said: “In the short term there will be limited impact resulting from the UK leaving the EU, but if exchange rates stay as they are, in particular, the exchange rate between sterling and the US dollar, then there will be a material benefit in the year ending 31 March 2018.”

This will be a welcome boost for the company, which reported sales of £32.8m, down 4% for the year to March 2016. North America is the company’s largest market, accounting for £15.8m of sales.

The company said sales in the US were down 9% in local currency during the year, but only 2% lower when converted into pound sterling. The further sharp weakening in the pound, which tumbled to a 31-year low against the dollar on Tuesday, is expected to provide a major boost.

“The majority of the US … turnover is sourced by exports from the UK parent company,” the accounts stated. They added that Osborne & Little took measures to reduce exposure to currency fluctuations but this was only in the near term.

The company is controlled by Sir Peter Osborne, the former chancellor’s father. It reported a pre-tax loss of £377,000.