Individuals requiring right to work in the UK
If you require right to work in the UK, this must be obtained and original documentation presented to HR before you commence employment.
There are various visas available and will depend upon your personal circumstances and the work you wish to carry out in the UK. Visas have different working conditions and may restrict the holder to defined hours, post and employer. It is important that you understand your visa and ensure you do not breach the conditions. You can find out if you require a visa and the associated conditions on the UKVI website
Nationals of countries newly joining the EU ("accession states") do not always have the same rights to work in the UK as other EEA nationals. Currently Croatia is an accession state and nationals would require authorisation to work prior to commencing employment.