Northern Rock is to embark on a £14bn mortgage sales drive to resuscitate Britain’s sluggish housing market, fuelled by a hefty injection of fresh government funding for the state-owned lender to be announced on Monday.

The Newcastle-based lender will split into a “good bank/bad bank” structure, allowing it to lend about £5bn of new mortgages in 2009 and £9bn from 2010, depending on market demand and funding, the government said on Sunday night.