This letter only states that they have refused to allow you entry to Ireland because the purpose of your visit, as determined by the Irish immigration authorities, wasn't the one you have originally expressed. This is not the same as deportation but the effect in the end may be similar.
As far as UK is concerned Ireland and UK it is quite likely that the information has been shared between immigration authorities in UK and Ireland due to Common Travel Area (CTA) in existence. According to the paper from Irish Centre for Migration Studies
A little-noticed but significant side-effect of the CTA, which has been seen as an internal arrangement between the UK and Ireland, is that it has in practice largely aligned Irish policy concerning external immigration with that of the UK. Thus, the Home Office ‘black book’ of persons refused leave to enter the UK was circulated to the Irish authorities and Irish diplomatic missions and used to ban entry to such persons to Ireland.
The same is likely true in reverse, but there is definitely information sharing between the 2 countries, so more likely than not you will be refused entry to the UK
And finally if your answer on another question is any indication you were already refused to land in the UK
