What is your nationality?
Where will you be travelling from?
How will you travel. Car/Ferry? Flying? Which airline?
Ryanair are very strict about producing photo identity. This is from their web site:
"A valid European Economic Area (EEA) driving licence with photo, presented by a passenger whose place of birth is within the EEA is acceptable only for travel on internal flights within the UK, internal flights within Italy and UK-Republic of Ireland-UK. "
The chances are that the answer to your question is "Yes".