My Irish passport expires on April 23rd.
A colleague mentioned a passport can be refused if it is within 90 days of expiration. Is my passport valid to use up until April 22nd?
More importantly: can I travel to and from the UK within the week before it expires?
According to Entering the UK:
You can enter the UK with either a valid passport or a national identity card issued by a EEA country. It must be valid for the whole of your stay.
The UK does not have a requirement for the passport to be valid for a certain amount of time (unlike some countries). It need only be valid for the time you spend in the UK. So, in your case you can travel to the UK as long as you leave the UK no later than April 22nd.
Note also that since you're from an EEA country, you can use a national identity card instead of a passport. However I don't know whether Ireland issues national identity cards that satisfy this requirement.
Many countries are concerned about visitors who come and who do not want to leave (or who cannot leave for some reason). To make sure that they can throw overstayers out again, they insist on passport validity beyond the intended period of travel. Three months or 90 days is common.
As an Irish citizen in the UK, you are not requesting permission to visit. For the time being, you are exercising your EU treaty rights to travel and work. The UK border officials are required to give you every opportunity to prove your citizenship. A passport is such a proof, up to the last day.
