A few financial parameters have emerged on the portfolio of branches and customer relationships being sold in Britain by Royal Bank of Scotland.National Australia Bank is a probable bidder in the process, as are Virgin Money, Santander and a handful of private equity firms.The Sunday Times reported that the loan book attached to the 318 branches was £24 billion, and about a fifth larger than foreshadowed by RBS, using older data, in November 2009. There's a variance in British media reports over the percentage of loans that are business loans. The Sunday Times reported that it was "roughly half" and the BBC reported that it was 70 per cent.One rationale for the sale (forced on the bank by the European Union) is to increase competition in the supply of banking services to business in Britain.The newspaper reported that about £7 billion of the loans were to retail customers, and mainly mortgages.The Sunday Times also reported that the buyer would need to support the business with around £2 billion of capital, citing documents circulated to prospective buyers in the middle of last week.Any buyer will need to quickly refinance £3 billion in liabilities now funded by Treasury under the Special Liquidity Scheme.