The UK government’s plan to temporarily nationalise stricken mortgage lender Northern Rock reduces some of the risks for investors’ in its asset-backed securities but threats such as the consistency and timing of bond prepayments remain, according to analysts.

Lehman Brothers said in a report the UK government’s move was “positive” but it ultimately does not provide complete closure for investors over the future of Granite Master Trust, Northern Rock’s £50bn (€97.4bn) securitisation vehicle.