Northern Rock, the Government-owned mortgage lender, has been forced into a raft of new sub-prime writedowns that will see its total impairment charge nudge £400m. Sunday Telegraph

The bank will admit in its annual report that its structured investment vehicles are now so toxic it has had to nearly double an initial writedown taken in December of £118m on investments of £319m.

In total, writedowns are understood to have increased by 40% from £281m in December to around £395m this month, with the Rock’s £167m US CDO portfolio virtually worthless because of deteriorating economic conditions.