If RBS succeeds in making Mr Montague bankrupt he will be forced to resign as a director of Tiphook, putting in jeopardy the company's recovery plan under incoming chairman Ian Clubb.
The petition is for pounds 2,296,176.03p. The sum is part of a much larger amount of personal borrowing from several banks by Mr Montague, and relates to his 1,300-acre Pusey estate in Faringdon, Oxfordshire. Mr Montague bought the estate, which includes a magnificent Georgian mansion, for more than pounds 7.5m from Sir Simon Hornby, WH Smith's former chairman.
Another big lender to Mr Montague is Commerzbank.
The bankruptcy petition only came to light at Tiphook's stormy annual meeting yesterday, and after Mr Clubb had stressed that Mr Montague's continued role as chief executive was necessary for the recovery of the company.
Mr Clubb told shareholders at the RAC Club, Pall Mall, London: 'My job is to take things forward and try and restore the company to financial health.
'It is my strong view that without Robert Montague . . . it will not be possible for me to achieve my goals for the shareholders.'
Sources close to RBS insist the petition is nothing to do with Tiphook but solely concerned with Mr Montague's personal borrowing.
Coincidentally, RBS is also company registrar to Tiphook. Banking sources insist that quite separate divisions within the bank would deal with Tiphook and with Mr Montague's personal affairs.
The bankruptcy petition was brought to shareholders' attention by Paul Snook, a director of accountants Buchler Phillips, a proxy representative for US ADR- holder Lehman Brothers. Mr Snook said that a petition had been lodged with Oxford County Court on Wednesday. However, the identity of the petitioner and the amount involved only emerged after the meeting.
When RBS's role was revealed, a Tiphook spokesman responded saying: 'Mr Montague's personal finances are his own affair and until we are fully appraised of all the facts that remains our attitude.'
Mr Montague was unavailable for comment.
Earlier, at the meeting, Tiphook's outgoing chairman Rupert Hambro told shareholders that Mr Montague denied any knowledge of the petition. Mr Hambro even described suggestions that a bankruptcy petition had been served at all as 'scurrilous'.
A number of shareholders barracked the board over Tiphook's dire financial performance, its prospects for survival and the huge salaries and payoffs made to directors. Mr Hambro said he could not justify the huge sums paid to Mr Montague in the past.
'I am not saying that I can stand here and justify what Mr Montague was paid in 1993 . . . I can't justify the past, I agree it's wrong,' Mr Hambro said.
Mr Montague's total remuneration last year, including bonus, amounted to more than pounds 1.3m. He has been granted options to buy more than 4.5 million Tiphook shares, yesterday down 1p at 37p, at prices between 20p and 100p. These options are subject to certain charges in favour of Barclays Bank.
Mr Montague's estate includes a pheasant shoot that he has enjoyed with friends such as Henry Keswick, chairman of Jardine Matheson, and Sir Adrian Swire, chairman of John Swire and Sons, which is the owner of Cathay Pacific Airlines.