Sir Sandy Crombie, the chief executive of Standard Life and the architect of its demutualisation, is to join the board of Royal Bank of Scotland, The Daily Telegraph has learnt. The appointment of Sir Sandy, 60, who is expected to join RBS in July, will be confirmed on Friday morning. He will become the bank's senior independent director and will be charged with leading a dialogue between RBS and its leading shareholders.Britain's economic stability has come under the gravest scrutiny yet again after the Government's debt was placed under official review by the world's leading ratings agency for the first time in more than three decades.In a decision which sent shivers through the currency, gilt and stock markets, Standard & Poor's announced that it had put Britain's AAA rating onto "outlook negative" reports the Telegraph.Major Australian investors in Rio Tinto have called for changes in the group's planned tie-up with Chinalco.The calls come as state-owned Chinalco reportedly prepares to alter the terms of the deal after recent gains in commodity prices made its proposal less attractive, reports the Telegraph.Two investment consultants were arrested yesterday by police investigating an international fraud involving potential losses of £250m. Another man is being hunted in connection with the allegedly bogus high-yield fund in which 600 investors around the world lost money. The inquiry is focusing on the activities of three firms: Business Consulting International (BCI), John Anderson Consulting and Kenneth Peacock Consulting, reports the Times.The Obama administration is preparing to steer General Motorsinto bankruptcy next week, according to The Washington Post.Under the GM draft bankruptcy plan, the company would receive just short of $30bn in additional federal loans, as it seeks to shrink and re-emerge as a global competitor, the newspaper reported.Meanwhile, Edward Liddy, the government-appointed chairman and chief executive of AIG, is to leave the stricken insurer after only eight months in a move that will allow the Obama administration to choose its own leaders for the troubled group. The AIG board, which is now controlled by government appointees, said it would split the role of chairman and chief executive and look at external and internal candidates for those positions, reports the FT. British Land is positioning itself to return to the property market to exploit any future recovery after writing off more than £3bn from the value of its estate last year. The UK's second-biggest real estate investment trust reported a 28 per cent drop in the value of its portfolio to £8.6bn which, along with the company's £740m rights issue this year, took net asset value per share down 64 per cent to 398p, reports the FT.The billionaire Reuben brothers have put in a £40m bid for Premium Bars & Restaurants that would cause the troubled operator of the Living Room and Prohibition chains to undergo a pre-pack administration, The Times has learnt.David and Simon Reubens, who hold a 32.5% stake in the AIM-listed group, have offered to buy all but five of PBR's 48 outlets. The offer would see shareholders lose all their money and the banks write-off up to £10m of debt.Bramdean Alternatives, the investment trust managed by Nicola Horlick, yielded to shareholder pressure yesterday and pledged to break itself up if it received no takeover bid within ten weeks. The listed company, which is under siege from Vincent Tchenguiz, the property tycoon, pledged to start realising its assets and pay back money to shareholders if no bid materialised by July 31, reports the Times.Borders UK has appointed a restructuring company to advise it on how to close some of its underperforming stores, raising questions about the future of the bookseller. The Independent has learned that Borders UK, which was bought by the private equity company Risk Capital Partners in 2007, has been working with RSM Bentley Jennison to review a range of potential restructuring options.