The trustees of the defined benefit pension scheme of Northern Rock today unveiled a new obstacle to a potential long-term rescue of the stricken mortgage lender after calculating that it was in deficit by about £100m (€132m).

In a letter to scheme members, the trustees said the defined benefit scheme has gone from a surplus in April 2007 to a £100m deficit as a result of more conservative investment strategies and cautious actuarial assumptions adopted in the wake of Northern Rock's financial crisis.