Chris Froome believes retaining his Tour de France title will be the toughest challenge of his career.

The 31 year old arrives in France on the back of an impressive win at the Criterium du Dauphine and he will be supported by one of the strongest lineups ever assembled by Team Sky for the Tour.

But Froome feels that the competition for the yellow jersey is a lot fiercer this year - in number and ability.

The two-time Tour de France winner said: "I feel very honoured to be leading such a great group of guys. I really do feel as if we've got all our bases covered.

"Personally I feel I'm in great shape coming off the back of the Dauphine and I'm ready for this year's Tour de France.

"But this year, more than any other, the level of competition is that much higher. I feel as if I've got more rivals and the level of my rivals is that much higher."

This year's route features more climbing than in previous editions and Froome believes the team around him will excel when the race hits the mountains.

He added: "It is very much a climber's route this year. Even the two time trials, one is pretty much straight uphill and the other has two climbs on it - they are time trials where climbers will do well. That's why we've selected this team around me - everyone here can climb.

"Having said that we definitely can't take anything for granted. Anything can happen along the way and there's a lot of factors outside of our control.

"But we're here with a team that's ready to go and has the potential to get the job done. This is the biggest race in our calendar. We love being here and we love racing in France."

The victory at the Dauphine was just Froome's second of the season, after winning the Herald Sun Tour in February, and he feels as though he has peaked a little later this year.

"In previous seasons I've been in top shape in the spring and then basically tried to hang onto it," he explained. "I feel as though I've only really just got there now. I'm really starting to feel I've reached that level again.

"Hopefully because we've delayed everything I'll be able to hang onto the form a little longer and into the Rio Olympics."

Geraint Thomas will be one of Froome's key lieutenants across the race and the Welshman is solely focused on helping his team-mate to success, following a tough challenge at the recent Tour de Suisse.

Thomas said: "Suisse didn't really go to plan for me. I wasn't going badly, but I certainly wasn't going as well as I'd hoped to be. That was a big disappointment, but I've rested up, freshened up, and I'm raring to go to do my job for Froomey.

"Hopefully I'll feel good when we start climbing and if I'm up there, anything extra will be a bonus. I'm not really thinking about my personal ambitions at the minute."