Activist investor Palliser Capital has built a stake in the British testing and certification group Intertek, Bloomberg News reports, citing sources.

The news follows Intertek's rejection of a third offer from private equity firm EQT valued at 58 pounds per share, or approximately 8.9 billion pounds. Several major shareholders are reportedly pressuring Intertek to enter talks with EQT, with some hoping for a sweetened bid of 60 pounds per share or more.

Investment fund PrimeStone Capital has also criticized Intertek's management and corporate governance in a letter to the board. The fund believes EQT's offer represents a significant premium compared to other UK acquisitions in recent years.

Meanwhile, Intertek is continuing its strategic review and states that interest in its Energy & Infrastructure division has been encouraging.