An acrimonious tussle between two of Britain's most celebrated entrepreneurs took a new twist yesterday when Sir Stelios Haji-Ioannou, founder of Easyjet, urged shareholders in Regus to turn on Mark Dixon, the office rental group's founder and chief executive.

Regus yesterday brushed off fears about the health of the office business with stronger-than-expected results for the first four months of the year. Its net cash balance rose 14 per cent year-on-year to £115.7m, as Mr Dixon pursues a conservative financing strategy ahead of any downturn. Revenues at actual exchange rates rose 24 per cent to £335m.

But when shareholders convene at today's annual meeting they will have something other to consider than yesterday's 15 per cent jump in Regus's share price.

Sir Stelios wrote to investor groups last week arguing Mr Dixon is misusing shareholders' funds. He also questioned the independence of the Regus board.

The dispute arises from Sir Stelios' entry into the serviced office market in November. The entrepreneur is threatening to sue Regus after its August acquisition of a 49 per cent stake in Nuclei, which trades as Easy Offices, saying the move was designed to thwart his own venture, Easyoffice.

Sir Stelios contends the purchase came after a confidential discussion with Mr Dixon over a possible joint venture the previous March. Yesterday he called on Regus shareholders to ask why it had bought a stake in a company already engaged in a branding dispute with his "easy" empire.

Mr Dixon attacked Sir Stelios' broadside as a "publicity stunt".