A recent letter regarding the significance of the CTA submitted by the Irish Ambassador to the UK, Adrian O’Neill, to the Irish World, a weekly newspaper for the Irish in Britain. See link below.
Letter seems to strongly indicate that despite the UK leaving the EU Ireland will still enjoy certain privileges in the UK under the terms of the CTA (Common Travel Area) including social security benefits. This is indeed good news as it should mean continued access to the UK state pension and the voluntary contribution facility to boost your UK state pension entitlements.
So, even if access to social security benefits, including the UK state pension, ceases for EU citizens Irish citizens will still enjoy those benefits under the CTA regardless of Brexit. Interesting, I hope the Ambassador is right!!