Sheffield-based law firm Irwin Mitchell is working with investment bankers at Rothschild to explore plans for an initial public offering, according to news reports.

Analysts said the firm, which employs more than 2,600 staff, could secure a stock market valuation of up to £500 million.

Responding to the speculation, Irwin Mitchell said: “We’ve taken no decision to introduce external investment.

“We remain in a strong position financially with our existing bank facilities offering us sufficient firepower to invest further in the growth and transformation of our business.”