Briton Jenson Button believes his Honda team are failing to match the development pace of their rivals as the Japanese squad continue with their dismal season.
Honda, one of the favourites to fight for race wins ahead of the start of the season after a promising showing in winter testing, have finished on the podium only once in eight races.
The team endured another disappointing weekend at Silverstone, with Button retiring with an engine failure just ten laps into the race after having started from 19th place.
His teammate Rubens Barrichello finished in tenth position despite having started from sixth to complete the first point-less weekend for the team.
Button believes Honda have gone backwards since the start of the season, but the Briton is confident they can rectify the situation.
"I wouldn't say otherwise," said Button when asked if his team were on a decline. "We are not as strong as we were at the start of the season and a lot of that is because the top teams have developed and we haven't.
"There are many areas that we need to improve in, we know that, the full size wind tunnel is going to help us a lot, and that is a big difference. Throughout the season little bits and little bits make a big difference and we haven't had that with our wind tunnel.
"We would have to test the parts after we had tested them in the wind tunnel to see if it was working, before we put in on the car for the race. A lot of teams put the car in the wind tunnel and stick it straight on the car in the race so they are non-stop.
"That is what we have lacked. That is not the only problem because we have other areas we need to work on, but we know what they are and we will get better."