The party's economic spokesman said he disagreed with the argument that, because St George was from what is now known as Turkey, the national day is irrelevant.
Asked whether he would have been welcomed by a 3rd-century Ukip as a skilled migrant, he replied: "Well, I guess dragon-slaying is a skill but whether it is one that's in short supply for the needs of the British economy, we will leave to our migration commission.
"Whenever the issue of St George's Day comes up - and I can predict this on Twitter today - there will be many left-centre people who will tweet the fact that St George was from what's today known as Turkey as if that is the start, finish of conversation and that makes St George's Day irrelevant or illegitimate or ridiculous.
"I completely disagree ... I'm not particularly hung up on where St George came from. I'm more interested in what St George's Day can represent."
Mr O'Flynn was also asked whether English people should be given priority access to public services over Scottish people who have moved south of the border.
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He said: "Ukip believes in the UK. I don't think there is any distinction between the right of someone from Scotland and the right of someone from England to access public services."
On the wider immigration question, he said: "Our approach to immigration begins with the priority of what's good for Britain and the British people."
The nation's first priority, he stressed, is to look after the British people.