Traffic police have stepped up their checks on the capital's 40 horse-drawn carriages or botticelle during the current heat wave, following orders from Rome's newly-installed mayor Ignazio Marino.

The checks are to ensure that the horse's owners are in compliance with regulations, in particular that the animals are not put to work at the hottest time of the day, between 13.00 and 17.00. The controls will also see that horses receive sufficient water and rest.

Under city law the horses are not allowed to work for more than six hours a day and must be allowed to rest in the shade between tours.

Over the years there has been increasing opposition to the botticelle from animal rights' activists who say the conditions in which the horses work are cruel and dangerous.

Last summer an exhausted horse collapsed in Piazza di Spagna, under the strain of carrying six tourists in 40 degree heat. The incident made headlines after the driver attempted to beat the horse back to work and only stopped following the intervention of police.

A month later there were violent scenes in the same square when animal rights activists and botticelle drivers clashed, resulting in three arrests.