The deadline to take over the UK’s National Express Group is expected to be further extended by two weeks to allow bidders more time to prepare a $1.26bn (£765m) offer.

The rail company will request regulators to give more time to its bidders, the Spanish Cosmen family and CVC Capital Partners, to perform due diligence before they make the formal offer.

The “put up or shut up” deadline was earlier extended from 11 September to 25 September by the UK’s Takeover Panel.

The rail company has been a takeover target ever since it reported a $1.7bn debt and was forced to give up its East Coast Rail franchise.