New British bank venture NBNK is interested in joining the bidding for state-owned lender Northern Rock, sources said.

The move raises the possibility that NBNK could combine Northern Rock with around 630 Lloyds bank branches it is also eyeing to create a powerful new competitor to Britain's established banks.

NBNK, set up last year by Peter Levene, chairman of the Lloyd's of London insurance market, is headed by chief executive Gary Hoffman, who was boss at Northern Rock until last November.

As part of his exit terms, he was barred from making a bid for Northern Rock until next month.

The sources said Hoffman had asked Northern Rock and UK Financial Investments, which oversees Britain's state-owned banking assets, for the ban to be lifted early so he could make a bid, and both parties had agreed.