Bromances gone bad

Lewis Hamilton's arrival at Mercedes at the beginning of last season was seen as the beginning of a great bromance.

As replacement for Formula One legend Michael Schumacher, the brash Brit - world champion in 2008 - fitted perfectly into the ambitious team's plans.

And pairing him with friend and rival from childhood, Nico Rosberg, looked to be the script for a buddy road movie.

Hamilton told The Guardian last year: "I have never laughed so much than when we were racing together. Nico was kicking everyone's butt at that time. We had some great races together and built a great relationship."

So far, so Disney.

But F1 isn't European junior karting and in the premier motor sport class it has been Hamilton doing the butt-kicking.

Last season, as Red Bull's Sebastian Vettel cruised to a fourth successive world crowd, Hamilton and Rosberg seemed to strengthen their friendship.

But this year, with the rest of the field choking on Mercedes' exhaust fumes under the new regulations, it seems that even going into just the fifth race of the season - this weekend's Spanish Grand Prix in Barcelona - the title is a two-horse race between the team-mates.

With Rosberg having won in Australia and Hamilton the next three races, Mercedes' dominance is causing trouble in paradise.

With his lead at the top of the standing down to four points, the normally affable Rosberg is becoming tweezer-lipped on the topic of Hamilton, while the Briton's competitive streak is best seen on the track, where he has twice resorted to tactics that left the German seething.

In the cut-throat world of F1, your team-mate is always the one you need to beat, and with a world title on the line - and no apparent team orders - the Rosberg-Hamilton love-in is under pressure.

This season's regulation changes have so blown away the rest of the field that F1 bosses must be praying the bit of a niggle develops into a full-blown feud to keep racing fans interested.

F1 has had a long history of great team-mate rivalries based on mutual dislike, particularly in the modern era.

The greatest was Alain Prost and Ayrton Senna at McLaren. The quiet Frenchman and the intense Brazilian started out quite close, but once they were paired at the dominant team of the late 1980s, respect remained, but a steely-eyed hatred lurked just beneath the surface.

The feud was apparently triggered by Senna allegedly reneging on a pre-race deal not to compete the first corner at Imola in 1988.

Once Prost had retired, and shortly before Senna's death at Imola 20 years ago, they resumed their friendship.

Hamilton himself was involved in a year-long sulk-off with Fernando Alonso when the two were teammates at McLaren in 2007. The two-time champion Spaniard was unimpressed by what he regarded as favouritism by the team towards the youngster.

The spat between Nigel Mansell and Nelson Piquet arguably cost both the title (Prost won) in 1986. This was a dislike both on and off the track.

Vettel, having outlasted one troublesome Aussie team-mate in Mark Webber - they took each other out in 2010 and were barely on speaking terms when Webber retired last year - now has Daniel Ricciardo proving a bit of a handful.

Perhaps to liven up this all-too-quiet season, F1 should take a leaf out of Nascar's book and advise: "Boys can have at it."