The Office of Fair Trading has concluded that nationalising Northern Rock has had no 'significant adverse' impact on competition across financial services.

A report released today by the City regulator found that the impact of the public ownership of the Newcastle-based bank on the current account, savings and investment market has been 'minimal or insignificant'.

It also found that the state-owned bank, which was the fourth-biggest mortgage lender in 2007, did not use its nationalised status to borrow from wholesale markets to offer rates that distorted the mortgage market.

The Times