Citizens of the European Union do not need a visa to enter the United Kingdom, but do need to travel with their passport. Citizen cards will not be accepted after October 2021. If you are from any other country, find out about visa requirements before you travel by visiting http://ukvisas.gov.uk. If you require an invitation letter, please contact vivien.thomas@iop.org. Please note that invitation letters will only be issued to delegates who have paid the registration fee.