The police and council chiefs have revealed how an unknown saboteur has been deliberately killing street trees.

The situation has become so bad that the roots of newly planted trees will be surrounded with cages in one location to stop attempts to 'poison' them.

It has emerged that someone has been pouring motor oil into the ground around newly planted trees in Raleigh Road, which sits on the Kew side of the A316.

The police in the area have sounded the alarm and revealed they are working with the Council and local residents to replace the 'poisoned' trees.

The police have delivered a letter to local residents to explain efforts to tackle the sabotage, which appears to have been going on for several years. They are asking people to come forward with any information.

The letter states: "In recent year, the Council has tried planting street trees at the south west end of Raleigh Road on several occasions but have found that new trees have failed to thrive, and this appears to be related to the confirmed presence of motor oil in the tree pits and watering tubes, which have had a toxic effect and caused the trees to decline."

It adds: "The Council is keen to see trees thrive in the street scene and will now be planting replacement trees. As part of the planting process the contaminated soil will be removed and replaced and protective cages will be erected to surround the new trees.

The letter says Council will be monitoring the trees, but the police are also asking residents to watch for suspicious activity and report any concerns to them via [email protected]