World champion Lewis Hamilton has reiterated his opposition towards the Halo safety device after threatening not to use it should it become mandatory in Formula One.

The controversial concept, which was pioneered by Hamilton’s Mercedes team and is designed to improve driver head protection, has been tried out by Ferrari at this week’s final pre-season test in Barcelona.

But after describing the safety device as the “worst modification in Formula One history”, Hamilton went one step further by saying he would even contest using it.

The FIA, Formula One’s governing body, announced last week that it intends to improve cockpit protection for the 2017 campaign with the Halo their preferred option.

“If it is going to come in I hope we have an option to use it or not because I will not be using it on my car,” Hamilton said on Friday. “I hope that’s not what they’re bringing, I really do. Ultimately it’s the driver’s protection so we should have a choice individually.

“I like it the way it is now and when I get in the car I know there is a certain risk. Safety is a very, very important issue for sure, but there are risks that we take and you have to decide how much of a risk you are going to take. For me I would rather drive without it and risk it.”

Meanwhile, Sebastian Vettel posted the fastest time on the fourth and final day of pre-season, but still couldn’t match Ferrari team-mate Kimi Raikonnen. The German four-time world champion clocked 1min 22.852sec to lead the time sheets with Hamilton down in fifth.

Spain’s Carlos Sainz Jr was second-quickest in a Ferrari-powered Toro Rosso, clocking 1:23.134.

Raikonnen managed the fastest time this week when scorching around the Circuit de Catalunya in 1:22.765 on Thursday.