SPA-FRANCORCHAMPS, Belgium --- Arrows has said it will not be racing in Sunday's Belgian Grand Prix.

Arrows had hoped to complete its sale to an unnamed American investor but it said in a statement that had not been possible.

A spokeswoman said they would be packing up immediately and returning to Britain.

"The legal teams are still working through the detailed documentation that supports the sale of Arrows," the statement said. "Professional advisors on all sides have been working extremely hard all week to finalise the deal in time for this weekend.

"Unfortunately, due to the sheer amount of paperwork involved, the process cannot be completed by close of business today.

"Consequently the team has been advised to do nothing that could jeopardise the successful completion of the transaction so will not race in Sunday's Belgian Grand Prix."

The decision left the starting grid with just 20 cars for the second race in a row and means Arrows, which failed to show up in Hungary two weeks ago, has not now competed since Germany on July 28.

It also left Arrows facing possible sanctions with its Formula One survival still in doubt.

An International Automobile Federation (FIA) spokeswoman said the sport's governing body had requested an official explanation from the team.

Arrows turned up at Spa with three cars, but only one named driver, Brazilian Enrique Bernoldi, and a lingering question mark over its engine suppliers Cosworth's willingness to provide power.

Germany's Heinz-Harald Frentzen was also entered as number two driver for procedural reasons but he left the team in July and did not travel to Belgium.

Arrows has been in trouble for months, fighting to stay alive in a year that has already seen the French Prost team go to the wall.

Their problems burst into the open at the British Grand Prix in July when the team's partner Cosworth demanded payment before releasing engines and team boss Tom Walkinshaw dipped into his own pocket to keep them going.

Earlier that week, the team had been barred from seeking fresh investment without the consent of investors Morgan Grenfell following a High Court injunction.

The team turned up at the subsequent race in France, but skipped free practice and made no more than a token attempt to qualify.

After a warning that such behavior could lead to it being kicked out of the championship, Arrows competed in Germany but missed Hungary due to force majeure -- or unavoidable circumstances.

Niki Lauda, the Jaguar boss who oversees Cosworth, said in Hungary that Arrows had not paid for its engines for that race and legal action could be expected.

To add to Arrows troubles, the team faces a winding-up order in London on September 10 from former driver Jos Verstappen and another unnamed party.

The Dutchman, who is also claiming some unpaid wages from last year, was replaced before the start of the season despite having a contract for 2002.

Should Arrows be declared insolvent, it will lose its right to compete.

Arrows did not take part in Friday's free practice, but Bernoldi at least took a fatalistic approach.

"The situation is bad at the moment but I think, if we can get an investor, we can sort out the problems and start competing again," said the Brazilian. "I have to say I am a little bit used to it because I had this situation in Silverstone, Magny-Cours and Hungary. So this is the fourth time. But I can't do anything."