The Thai company’s offer of £2.40 per share was recommended by the Cove board in May when it was increased above the £2.20 per share offer by supermajor Shell.

But since the offer has been open, PTTEP has only been able to secure valid acceptances from shareholders for 1.2 million shares, or 0.25% of Cove’s total issued capital.

That level was the same when the company last extended its offer on 25 June.

Cove