Ripplewood, the private equity group, is understood to be ready to return with a bid for General Motors Europe should the carmaker's Canadian suitor fail to complete its acquisition, The Times has learnt.

About 5,000 British jobs hang in the balance at Vauxhall as Magna International, the Canadian car parts supplier, trawls through the accounts of the Luton-based carmaker.

Magna's offer to buy a controlling stake in GM Europe - which owns Opel in Germany and Vauxhall in the UK - is conditional on the completion of due diligence. Magna is also eager to grab state aid from Lord Mandelson in return for guarantees about the future of the Vauxhall workforce.

While representatives from Lord Mandelson's Department for Business, Innovation and Skills (BIS) are due to meet Magna officials in London this week, there remain doubts over whether Magna will complete the deal. Unite, the union, which represents Vauxhall's workers, has scheduled no meetings with Magna this week.

Ripplewood was one of four interested parties considering a bid for GM Europe in May, but it was forced to withdraw from the bidding after Magna was picked at the end of last month as the preferred bidder.

While the terms of Ripplewood's interest were not made public, the approach was actually made by RHJ International - a related Belgian holding company. While RHJ International is independent from Ripplewood, the two firms were founded

and are run by the same executive - Timothy Collins. RHJ International has a number of investments in the car industry - namely controlling stakes in Asahi Tec, of Japan, Honsel, of Germany, and Niles, of Japan - all of which are car component companies. Mr Collins, who sits on the main board and is also chairman of the investment and strategy commission at RHJ International, and Leonhard Fischer, the chief executive of the group, spearheaded the approach for GM Europe.

RHJ International declined to comment yesterday. Magna International failed to return calls.

Magna has offered to pay €700 million (£610 million) for a 55 per cent slice of GM Europe and has handed over €300million of emergency funding to keep the group afloat. Of the 55 per cent stake, Sberbank controls 35 per cent. The American parent retains a 35 per cent interest and Opel workers keep another 10 per cent shareholding.

Garel Rhys, of Cardiff Business School and an expert on the car industry, said yesterday that, in his view, the area of most concern for Magna as it proceeds with its due diligence would be Vauxhall's Luton factory, which makes the Vivaro commercial van.

Professor Rhys said: “While the plant in Luton is owned by General Motors, the production side of it is a joint venture between General Motors and Renault. That venture is due to expire in 2012. Renault might renew but, then again, they might not if they don't like the look of Magna.”

The Department for Business, Innovation and Skills said that British car dealers had received 60,000 new vehicle orders since the scrappage scheme was introduced at the end of April. The programme, which gives motorists a £2,000 bounty if they scrap their old vehicles and agree to buy a new car from a UK dealership, was designed to provide a fillip to Britain's ailing automotive business. The 60,000 new orders are expected to translate into a substantial boost in the number of car registrations. In healthier times, the British car industry sees between 100,000 and 130,000 new car registrations a month.

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