Charles Green may yet face a challenge in his attempts to purchase the business and assets of Rangers in a £5.5m deal.

Herald Sport understands one of the previous bidders for the club intends to submit a new bid today, while another is considering their options but could also return with an offer that is higher than the price Green has arranged with the club's administrators.

A third, new bidder also intends to make a bid, having previously carried out due diligence.

All three groups believe the combination of higher purchase offers and the widespread belief among creditors that the £5.5m price undervalues the business and Ibrox, Murray Park and Albion car park, might be enough to pressure Duff & Phelps into backing out of their agreement with Green. The administrators insist that they have a binding contract with the Yorkshireman's consortium, but Herald Sport also understands Green has not yet raised all of the £5.5m, so may be unable to complete the purchase.

Green and Paul Clark, of Duff & Phelps, are adamant nothing would prevent their deal being completed following the Company Voluntary Arrangement vote at tomorrow's creditors' meeting. HMRC have indicated they will vote against the CVA proposal, which then prompts Green's deal to buy the business and assets for £5.5m. A creditor can challenge this by claiming the assets are undervalued, but that can be difficult to prove.

However, HMRC may apply pressure to Duff & Phelps to accept one of the new, higher offers, particularly if Green has not raised the full finance. Dave King, the Rangers director and the club's second highest shareholder, has also threatened to halt proceedings by seeking an injunction. "There is, in my view, no possibility Green will ever own the club," King said.

Herald Sport also understands one of the investors in Green's consortium is Rafat Rizvi, a British citizen who was once on Interpol's wanted list after being accused of stealing assets from Indonesia's Bank Century two years ago, a charge which he denied. Herald Sport believes that Rizvi is investing £2m in Green's Sevco consortium, with Mike McDonald, the former Sheffield United chairman, investing a further £2m. A third investor had agreed to put in £4m, but pulled out last weekend.

The Blue Knights, Bill Ng's Singapore consortium and a UK group all lodged bids before Duff & Phelps chose Green's offer.