McLaren test and reserve driver Gary Paffett has said that he does not understand why Lewis Hamilton has moved to Mercedes.
Hamilton joins Mercedes on a three year contract, having raced for McLaren since 2007.
"Some drivers move for their own certain reasons," Paffett said at the Autosport Show.
"I think a few of the times they move people don't understand it and I don't understand this one. I don't understand why he moved," added the 2005 DTM champion.
"I knew Lewis very well, I used to kart with him when he was ten years old. Lewis has solely been focused on winning, that is his aim. He wants to break records, he wants to win the most championships, win the most races and I see his best place to do that at McLaren. But obviously he wasn't comfortable there anymore or he fancied a new challenge."
Paffett, who finished a close second to Bruno Spengler in the DTM series last year, reckons that although Mercedes is putting effort into its F1 campaign, McLaren will remain ahead of them.
"Mercedes are a big manufacturer and they are putting a lot of effort into their F1 team. I'm sure they will get better, but I don't think this year Lewis is going to be in a better position than he would be with McLaren. But Lewis has is own reasons for what he's doing and I wish him luck with that."