The UK Coastguard is currently co-ordinating a search operation for an overdue helicopter in the Caernarfon Bay area in north Wales.
The privately owned helicopter with five people on board is believed to have left Milton Keynes earlier on Wednesday en route to Dublin.
The UK Coastguard said radar contact was lost on Wednesday afternoon.
A UK Coastguard helicopter, based at Caernarfon, in Gwynedd, has been conducting searches in the area.
A second search and rescue helicopter, based at St Athan, Vale of Glamorgan, joined the search on Wednesday evening.
North Wales Police has also been notified of the search operation.