Ex-Formula 1 world champion Jacques Villeneuve has claimed that the Manor Marussia team would be better off in a smaller racing series like GP2.
Manor managed to pull themselves out of administration, but have found themselves at the back of the F1 grid since resuming racing.
Villeneuve has suggested that the team's lack of competitiveness is why they shouldn't be in the sport, and the Canadian even warned driver Roberto Merhi that he is wasting his time combining racing for Manor with taking part in the Renault World Series.
Villeneuve told AS: "Merhi has little to do with that car that should not be in F1.
"[With] a car that is five seconds off the best, so far, these teams are not worthy of F1. It is better to be in GP2 or World Series – and, there, maybe they could be ahead. This is an expensive sport and [teams] must be competitive.
"F1 is an aspirational sport, where everyone wants to be, and it is expensive. Therein lies the appeal of F1. If, suddenly, Rolex watches were cheaper, they would not have the same value."
Manor failed to take part at the season-opening Australian Grand Prix, after a technical problem left both their cars in the garage at Albert Park last month.