This lovely hoverfly is a bumblebee mimic. It’s name is Volucella bombylans.
The female lay her eggs in bumblebee nests (and also in wasp nests). When the larva hatch they don’t generally harm the bee larva but feed on the debris at the bottom of the nest.
It’s a common species in Ireland. They are found in clearings and tracks in scrub and mature woodland or along field hedgerows.