Realistically the only hope of home-grown success on Sunday, Hamilton was left frustrated with the feel of his car following practice at an initially wet, and then overcast, Silverstone.
Steady rain throughout the morning virtually washed out the opening session, leaving the drivers with only 90 minutes of effective running under grey skies during FP2 on a drying track.
Team-mate Nico Rosberg again led the way, while Hamilton was forced to settle for the fifth quickest time, with Red Bull duo Mark Webber and Sebastian Vettel also ahead of him, along with Force India's Paul Di Resta.
A disgruntled Hamilton said: "I'm not happy with the balance of the car. I'm not enjoying it at the moment.
"I can't remember the last time I've felt so uncomfortable. I don't really know what it is.
"When you can't hook up (the car through the) Becketts and Maggots (corners), the rest of the track doesn't feel so good.
"I've got to go back and work on the set-up. It's just some bottoming with the car which is making it feel a bit awkward.
"But I'll do my best. We'll work on it and I'm confident we'll fix it."
In front of an 80,000 crowd, it was left to Di Resta to blaze the British trail, with the Scot finishing just over half a second down on Rosberg who set a time of one minute 32.248secs.
On a roll at the moment after taking points in six of the seven races this season, Di Resta said: "The car is working well, so hopefully we can carry the speed into qualifying.
"The focus is to keep improving because there's still some more speed in the car.
"We also need to remember it's likely to be quite a lot hotter today, so it's hard to predict how that will impact on things."
Regardless of the conditions, the McLaren continues to lack pace as Jenson Button finished 11th quickest, nearly 1.5secs down.
"The car doesn't feel too bad, and the balance is reasonable - it's better than it was in Canada - but we're still some way off the pace," said Button.
"Still, the engineers have lots of data to analyse, so they'll be able to find out whether the new parts have made the improvements they'd predicted."
Max Chilton finished 21st in his Marussia, with only Felipe Massa behind him after the Brazilian crashed his Ferrari for the fourth time in three race weekends.