Force India boss Bob Fernley has claimed that delays in his team's development ahead of the 2015 season have been caused by the financial collapse both Marussia and Caterham.

Fernley cited a "lack of substance" when the constructor blocked Marussia's re-entry into the sport.

However, the Force India boss has gone further, saying that both teams have had an impact on preparations for this year's car.

He told PA: "We've recently started working with Toyota's wind tunnel at their facility in Cologne. However, the Toyota people had agreements with Caterham, and quite rightly until they could resolve their Caterham issues we could not move in with our contract.

"We didn't get the go-ahead until early December, so we were behind schedule before we had even started.

"On top of that we've had a few issues with suppliers because they've obviously been hurt very badly by the Marussia and Caterham demises. They wanted payments up front, which hurt us cash-flow wise, and for one minute I don't blame the suppliers at all."

Force India finished sixth in the 2014 constructors' championship.