I have ICC, But they vary into different classes.
Coastal / Inland Power 10m/24m or 80GT Sail
Be aware though if you require inland waterways, you will
need an ICC with a CEVNI endorsement. RYA have details.:
Also you should carry registration documents, radio license,
evidence of insurance, VAT status and recreational craft
directive ( if required ).
As other people have commented, you may not get asked.
But as you asked the question !.