The plan for the partial break-up of Britain’s two state-owned banking behemoths is now public, rather than simply speculative, providing a few investment options for National Australia Bank in a banking market where management’s interest in the task is hard to work out.

Perhaps the fact that a selection of banking franchises of Royal Bank of Scotland and Lloyds are now on the market may provide an opportunity for NAB to decide to sell its British banking business as well, leaving the new owner the task of knitting together the Clydesdale and Yorkshire bank brands with one or more of the forced sales from RBS and Lloyds.

Or maybe NAB sees merit in having a go itself and making money from banking in Britain.

RBS overnight finally spelled out the assets actually for sale, under a strategy dictated by the European Union more than the government of Britain.

The key asset sale is the branch network, customer lists, and staff and supporting infrastructure covering RBS branch-based business in England and Wales, the NatWest branches in Scotland and also the “direct” small-business customer base.

RBS said the Williams & Glyn’s brand name (absorbed into NatWest in the 1980s) will also be available to an acquirer.

The business includes £20 billion ($A36.3 billion) of assets, £19 billion of deposits, 318 branches, 1.7 million retail customers, 230,000 SME and about 6000 staff.

RBS used December 2008 data rather than anything more recent. RBS said this represents a two percentage points share of the SME market in Britain and five percentage points of the mid-corporate market.

By comparison, NAB’s UK region, at September 2009, had £43 billion of assets, £34 billion of loans and £21 billion of deposits.

The timetable for this sale was not spelled out but the EU goal appears to be to steer this through over the next couple of years.

Some other RBS businesses are for sale, including its insurance business, which RBS does not have to sell until 2013, its commodities business, Sempra, and also its merchant services business.

Lloyds will be forced to sell its Lloyds TSB branch network in Scotland and additional Lloyds TSB branches in England and Wales, covering 600 branches in total. The bank must also sell the Trustee Savings Bank brand.

The Cheltenham & Gloucester mortgage arm and the online bank Intelligent Finance are also for sale.

Lloyds said this was equal to a 4.6% share of the current accounts market in Britain and about 19% of the group’s mortgage assets.