Barclays and ABN Amro have given themselves 48 hours to agree a merger after a rival consortium proposed a three-way break-up of the Dutch bank.

Barclays and ABN Amro are rushing to agree a deal before the end of the 30-day exclusive negotiating period, according to people familiar with the talks.

"It will be deal or no deal on Wednesday," said one person familiar with the matter.

The discussions have been lent a new urgency by the break-up proposal put to ABN Amro on Friday by Royal Bank of Scotland, Santander of Spain and Fortis, the Belgo-Dutch banking and insurance group. The consortium, which believes it could offer more than Barclays, is seeking access to ABN Amro's accounts.

However, efforts by Barclays and ABN Amro to complete their deal may be complicated by the movement in the two banks' share prices. ABN Amro's share price could rise today as investors anticipate the possibility of a higher bid from the consortium.

This could leave the Dutch bank's board facing the prospect of being asked to recommend to shareholders a deal with Barclays that values the bank at less than its current share price.

Meanwhile, the Children's Investment Fund (TCI), which has just under 3 per cent of ABN Amro's shares, has threatened legal action against the bank's supervisory board if it does not give the consortium access to the same information as Barclays.

"If other potential bidders are not allowed to do due diligence, [ the board] is in breach of its fiduciary duties," said Christopher Hohn, managing partner at TCI.

The rival consortium has given little indication of how an offer might be structured, although analysts say this will involve ABN Amro shareholders receiving cash as well as shares in two or three of the bidding banks.

ABN Amro is thought to be sceptical about opening up its books to rivals when there is no certainty they will make an offer.

For the past month, the Dutch bank has been pursuing a friendly merger with Barclays that would keep it more or less intact.

The discussions, which were accelerated over the weekend, envisage the creation of a giant bank capable of offering a broad range of financial products almost anywhere in the world.

The proposed break-up is more brutal. The consortium would carve up ABN Amro's operations between them. Royal Bank of Scotland would take the US retail banking operation as well as ABN Amro's wholesale banking business, which is largely based in London.

Santander would buy ABN Amro's operations in Brazil and Italy, while Fortis would acquire ABN Amro's Dutch business, as well as its fund management and private banking operations. - ( Financial Times service )