Retail tycoon Mike Ashley has blasted Andy Burnham's proposals to revive the British high street as "populist" and "too little too late".

The billionaire founder of Sports Direct and Frasers Group has written to the Prime Minister, accusing him of failing to tackle the cost of living with "delusional" policies. Frasers Group operates hundreds of stores across the UK, including on high streets and retail parks, meaning its cost base is directly exposed to changes in business rates policy.

The causes of the UK's rising cost of living "have not been assisted by recent government policies and are not going to be helped by your recent populist proposals," Ashley said, in a letter seen by City AM.

Ashley accused Burnham of prioritising media attention over practical solutions to help households and business, and took aim at the Prime Minister's "disastrous" position on business rates. Business rates, a tax on non-domestic property, have long been a flashpoint for retailers, who argue the current system burdens physical stores relative to online competitors.

Burnham has pledged to review how business rates bills for pubs and hotels are calculated, and has previously supported a tax on warehouses to fund lower taxes for high street shops.

Retailers have previously warned that a warehouse tax could push up prices for shoppers, and Ashley told Burnham the tax measure would be "delusional". Online players such as Amazon, which rely heavily on warehouse and logistics estates, would be among those most affected by any such levy, which supporters argue would rebalance the tax burden between online and physical retail.

"Rather than address the real underlying issues of how the country's financial affairs are managed, and supporting growth and entrepreneurialism in business, it is easier for you to pick topics which provide good media soundbites and the old salve of yet more regulation – which is not what the country needs to become competitive," he wrote.

"Shortsighted or populist reactions to underlying business challenges are not the answer. You have the chance to make a difference or get it horribly wrong."

Burnham resorting to 'band wagons'

The retail billionaire mocked Burnham's pledge to deliver "everyday fixes" on the cost of living, which have included a £2 bus fare cap and the removal of VAT on household electricity bills.

"This is a certainly a time for pragmatism and brave solutions but applying that to the underlying issues – not jumping on "everyday fixes" or band wagons that only address part of the problem," he wrote.

Ashley's intervention comes amid a growing backlash from business against Burnham's pledges to tackle the cost of living, as the costs facing businesses continue to rise.

On Monday, a group of influential business veterans, including billionaire political donor John Caudwell and retail bigwig Lord Stuart Rose, hit out at the "creep of taxes" hitting firms across the country (City AM).

In an open letter, the City grandees called on the government to rule out new taxes on founders, including levies on dividends, capital gains and business assets.

On Wednesday, Burnham told the Financial Times that he will tackle the "challenging" cost of business as he attempts to quash fears that October's Budget will bring another damaging tax raid on British firms (FT). The Budget has become a focal point for business lobbying, with firms across retail and other sectors seeking clarity on tax policy ahead of the fiscal statement.

In the letter to Burnham, Ashley also hit out at the Prime Minister's pledge to crack down on what he calls "fake" discounts (City AM). Aldi boss Giles Hurley has backed this initiative, accusing his supermarket rivals of misleading shoppers with loyalty pricing (City AM).

Ashley said: "The driving down of prices through discounting is what helps the consumer by giving them better value and helps with their cost of living. Driving down prices through discounting against an RRP can't be what you really mean when you talk about "rip off Britain"."

Before pushing into luxury fashion with Frasers Group's acquisition of Harvey Nichols and stake-building in Hugo Boss, Ashley made his name by selling cheap sportswear at Sports Direct. His retail career has been built on discount-led pricing, which goes some way to explaining his hostility to a crackdown on promotions marketed as discounts.