Re: @ Lysenko
By definition a customs union has a hard border. It has to, otherwise goods could go from the countries outside the CU over the border to the countries inside of the CU avoiding any and all tariffs and controls. If the UK wanted out of the CU, this is the logical result.
Ireland is an independent country, empire is no more, your suggestion that they stop being upperty and do what the their betters in the UK do is not realistic or useful.
By the way, the DUP have just scuppered a deal. They wanted no border, this was a deal which kept NI inside the CU, and they didn't want that either citing differences between NI and rUK, as if 12.5% corporation tax in NI and the GFA and all that entails aren't differences. Brexit is being driven by the Protestant Taliban which won less than 1% of the vote. Has there ever been a worse government in modern British history?