Tim Gosling in Prague -

Polish Prime Minister Donald Tusk has been pulled into the debacle surrounding the collapse of the OLT budget air carrier and the murky investment company behind it: Amber Gold.

Michal Tusk, 30, worked simultaneously for the state-run Lech Walesa airport in Gdansk and for OLT Express, which was one of the airport's clients, local media reported on August 13. OLT declared bankruptcy in July, while Amber Gold officially went under on August 13, although it had lost access to its accounts earlier in the month.

The PM is now under fire from the opposition over whether his son was involved in a conflict of interest in working for both a state-owned airport and a now-bankrupt low-cost airline, reports AFP. The fact that Amber Gold received permission from administrators to buy and operate an airline despite having been designated an illegal bank by financial markets regulator KNF is another that the opposition will push upon.

The investment firm disputed that, claiming that it was rather a company offering gold-indexed financial products. It then turned around and used clients' cash to acquire a controlling interest in the failed airline, and began regional flights in April, only to come crashing back down to earth four months later. While Amber Gold has promised it will pay investors back to the tune of €80m, few expect to see their cash again according to internet forums. KNF has the company under investigation.

Tusk the younger - presumably in a misguided bid to reduce the impact on the PM - said in a magazine interview published on August 13 that his father had warned him not to get involved with OLT Express and its owner, Marcin Plichta, who was convicted in 2005 of embezzlement.

The opposition is now asking Donald Tusk why he warned his son about OLT Express, but not the savers who were paying money into Amber Gold and may not have been aware of Plichta's conviction, points out The Wall Street Journal. They are also urging him to explain how both companies were cleared for operation by state regulators and justice authorities. The prime minister has so far declined to comment.