The lender's independent directors said they unanimously recommended that Shawbrook shareholders take no action in relation to the 842 million pound offer, which was announced on March 31.

The bank itself has already spurned the approach from buyout funds Pollen Street Capital and BC Partners.

In January, the consortium made an offer of 307 pence per share, which it increased to 330 pence in March.

Pollen Street currently owns 38.8 percent of Shawbrook and the joint private equity groups had previously said they have received letters of intent from other shareholders representing 6 percent.

Britain's smaller challenger banks have been increasingly seen as ripe for takeovers in recent months as a prolonged period of low interest rates has squeezed earnings and the pound's fall has made them cheaper for foreign buyers.

(Reporting by Clara Denina; Editing by Rachel Armstrong)