Bay tree under attack
 

Help! Our bay tree leaves are brown and dying. There are brown ridged pupae and small bright green caterpillars (both approx 1cm long) attached to the leaves. The leaves are sticky and some are matted together to provide homes for the pupae. We have tiny brown scatters of stuff (caterpillar poo?) everywhere (constantly hoovering it up). What on earth is it? The only info we've found on bay pests mention bay sucker - does this have caterpillars and ridged pupae? Can anyone advise on what this is and how we get rid of it?