A nine-rider breakaway group, which was seven minutes ahead of the main bunch, was approaching the Crow Road climb on the route from Edinburgh to Glasgow.

Environmental group This Is Rigged said on Twitter that they were responsible for the demonstration. Police Scotland said their Protest Removal Team had arrested five protesters.

Organisers the UCI confirmed that the race had been halted.

"Further to Police Scotland's confirmation of a protest in the Carron Valley area, which has temporarily interrupted the men's road race, we are working closely with all relevant authorities to minimise disruption to the race and also to ensure the safety of riders as our paramount concern," cycling's world governing body said in a statement.

Television pictures showed UCI president David Lappartient chatting to riders while others took the chance to sit in team cars or take on food and drink.

One of the riders in the lead group was Britain's Owain Doull. British Cycling is sponsored by oil company Shell.

The race was allowed to continue on towards Glasgow at 12.16pm with the leading group starting first in order to preserve their time advantage.

Several sporting events in Britain this year have been targeted by Just Stop Oil protesters including the Wimbledon Tennis Championships and the Ashes cricket test at Lord's.