Unknown insects

Unknown insects

Observation - Unknown insects - UK and Ireland. Description: found in a country lane near Keswick. Only one tree affected but was completely covered by what looked like a giant white spidersweb. There were thousands of small caterpillar like creatures crawling all over the tree. Are these ermine moths and do they d

found in a country lane near Keswick. Only one tree affected but was completely covered by what looked like a giant white spidersweb. There were thousands of small caterpillar like creatures crawling all over the tree. Are these ermine moths and do they damage the tree?