The future of Kimi Raikkonen should be clearer by next month, according to Lotus chief Eric Boullier.

The Enstone-based team are trying to convince the Finn, who is third in the drivers’ championship, to stay rather than move to Red Bull.

Raikkonen, along with Toro Rosso’s Daniel Ricciardo, is a candidate for the Red Bull seat being vacated by Mark Webber.

“Two years in a row we have closed the gap with Red Bull,” said Boullier.

“He wants to know if we will keep going like that.

“We are in discussions about the technical package we’ll have.”

Boullier said he expected a decision before August. He added: “Raikkonen is mature enough to decide for himself what is the right thing to do.

“There are some upsides to going to Red Bull and some downsides as well.”

After nine of this season’s 19 races, Raikkonen is third in the championship, 41 points behind Red Bull’s Sebastian Vettel and seven adrift of Ferrari’s Fernando Alonso.

Boullier confirmed the team had been late in paying Raikkonen.

Red Bull have said they will decide by the end of August whether Raikkonen or Ricciardo would be a better choice to partner Sebastian Vettel.

While Lotus want to keep Raikkonen, there are doubts about the future of teammate, Franco-Swiss Romain Grosjean, who has been inconsistent.