Formula One is coming face to face with the almost unthinkable: that it might have to negotiate the future without Bernie Ecclestone, the remarkable figure who has made it the second most popular sport in the world.

Ecclestone has gone from selling secondhand cars to building a multibillion-pound global empire, which he has run for almost 40 years. But all that could all come to an end following reports that he faces bribery charges over the sale of Formula One.

According to the Munich daily Süddeutsche Zeitung, Ecclestone faces charges in Germany relating to the Gerhard Gribkowsky bribery case. Investigations into the case are complete, according to the newspaper, and a Munich court is preparing to file charges in the case within a month, although there may be a delay as the details need to be translated into English before being delivered to Ecclestone's lawyers. The prosecutor's office said: "By German law, we cannot comment at this time. It could yet be a month or so before we can officially comment."

Ecclestone has maintained his innocence throughout, but has already admitted that he would be forced to resign if charged. He said earlier this year that the sport's owners, CVC Capital Partners, "will probably be forced to get rid of me if the Germans come after me. It's pretty obvious, if I'm locked up".

Ecclestone said on Wednesday: "They haven't told me [about the charges], that's the only problem. I suppose they will eventually, they're going to have to, obviously.

"To be quite honest with you I haven't done anything about any of these things. I haven't bothered. If I have to get bothered, then I'll get bothered."

When it was suggested to Ecclestone he was relaxed about the matter, he said: "Absolutely. 100 per cent. Sooner or later somebody will look into it, which they have, and then they will have to make a decision on what they decide."

Ecclestone has one of Germany's top law firms, Thomas Deckers Wehnert Elsner, as well as his lawyers in England working for him on the case.

His German lawyers said: "The documents with the charges from the Munich prosecutor's office have not been received. A statement is therefore not possible. The defence sticks to its view that Mr Ecclestone has neither committed bribery nor played any part in committing a fiduciary breach of trust."

Ecclestone will be 83 in October and there have already been reports that CVC is putting together a shortlist of names as it ponders over his successor.

Ecclestone said: "They said they had hired a headhunter to find somebody in the event that I was not going to be there – if I was going to die or something." But a potential court case could force the private equity company – and Ecclestone – to act sooner rather than later.

Nothing will happen immediately. If the indictment goes ahead it will have to be endorsed by a judge before a trial can go ahead, according to German law.

Gribkowsky, formerly the chief risk officer at the German bank BayernLB, was jailed for eight and a half years last year after confessing tax evasion and breach of trust towards his employer and being in receipt of corrupt payments.

He claimed Ecclestone paid him $44m (£29m) to undervalue Formula One's shares when the business was sold to CVC in 2006. Ecclestone said he paid the money to stop the German going to the tax authorities with "false evidence".

Suddenly, F1 has more to think about than quick-wearing tyres. There is a shortage of candidates to replace Ecclestone, who is simply inimitable.

From the sport, the favourite would be Christian Horner, the most successful team principal of the modern era; he has won three double world championships in the past three years and is also closer to Ecclestone than any other team boss.

Justin King, the chief executive of Sainsbury's and an avid motor racing fan, is thought to be another possibility.