Former Rangers owner Craig Whyte files for bankrupcy
The bankruptcy petition was filed at the High Court in London after Mr Whyte did not pay a judgment debt, plus costs and interest, currently worth £20.8m.
Whyte also faces criminal charges over his part in the Rangers takeover.
Ticketing firm Ticketus successfully sued the 44-year-old for damages in 2013 over his part in the takeover of the Ibrox club in 2011.
A spokesman for Ticketus said: "Ticketus is pleased with the outcome of today's hearing and will now support the appointment of a trustee in Bankruptcy, who can start the process of claiming any assets that Mr Whyte holds for the benefit of Mr Whyte's creditors."
Ticketus provided cash to help Mr Whyte purchase Rangers in 2011.
The agreement was later terminated when the club entered administration in February 2012.
In its action against Mr Whyte, Ticketus said that he fraudulently or negligently made representations which induced the company to enter into agreements related to the sale or purchase of Rangers season tickets, and claimed damages.
The firm sought £17.6m - the value of what it invested.
Whyte was absent when bankruptcy registrar Nicholas Briggs accepted Ticketus's evidence and ruled "the debts in the bankruptcy petition are true".
The registrar said Mr Whyte "was called six times this morning and staff combed the building" to see if he was present.
The registrar declared Whyte bankrupt, despite his non-appearance, after examining his written submissions to the court.
Matthew Collings QC, appearing for Ticketus, said there had been "a degree of radio silence" from Whyte, as he faces trial in Scotland.
Mr Collings said there was firm evidence that he was currently on bail somewhere in England, but it was believed his address was not being revealed "for his own safety".
The QC told the court: "Mr Whyte has said he is an unpopular man in Scotland.
"It is absolutely plain he has been in England. He himself says he provided an English address for the Scottish proceedings and the purposes of bail."
In April 2013, a High Court master ruled against Mr Whyte prior to a trial after Ticketus argued that the former Rangers boss had "no real prospect" of mounting a successful defence.
The master ordered Mr Whyte to pay £17.6m.
Mr Whyte bid to overturn the ruling on appeal was rejected at the High Court in London in November 2013.