Geraint Thomas has committed his future to Team Sky, although the Tour de France winner could return to playing chief lieutenant for Chris Froome in 2019.

Thomas, who succeeded four-time winner Froome in the Tour's yellow jersey in July, has agreed a new three-year contract with the British team which expires in 2021.

Thomas says there are no leadership guarantees in the contract, but he believes, just like in July, he will be given opportunities if he proves capable.

"As long as I am good enough, I will get those chances like this year," he said. "I wouldn't want to be the leader if I wasn't flying. That is not in my character. I am happy."

Thomas has been with Team Sky since their inception in 2010.

"It was good to finally get it signed and sorted," he added. "I am really happy. Obviously I listened to other teams and things.

"[But] at the end of the day, I sat down and thought about it properly. I feel at home with the team. This is the best place for me to be at my best. Why change it?"

The contract was announced ahead of the final stage of the Tour of Britain in central London on Sunday – Thomas was 36th with Froome 85th.

France's Julian Alaphilippe wrapped up overall victory as Australia's Caleb Ewan won the final stage on Regent Street.

As expected, the 77-kilometres eighth and final stage finished in a bunch sprint, with Ewan (Mitchelton-Scott) winning ahead of Fernando Gaviria (QuickStep-Floors) and Andre Greipel (Lotto-Soudal).

Germany's Greipel had won two stages earlier this week, but Ewan was triumphant on this occasion.

Alaphilippe protected his 17-second lead on Saturday's penultimate stage and completed victory ahead of Holland's Wout Poels (Team Sky) and Slovenia's Primoz Roglic (LottoNL-Jumbo).

Scott Davies (Team Dimension Data) was the highest-placed Briton in 12th place, one minute 54 seconds behind Alaphilippe.