On the Irish Sea the biggest ferry operator in this market area has confirmed that there will be checks, inspections and some new infrastructure for trade, and it wants to know what the UK government will pay for.

The plans, according to BBC News, will affect both trade with the Republic of Ireland and within the UK between Great Britain and Northern Ireland, as a result of Brexit.

Stena Line said that its working assumption was that new checks would be carried out in British ports.

Stena boss Ian Hampton told the BBC that though a managed exit was "positive" and the extent of new procedures could be lessened with a strong deal, "there's a border, and the border requires checks".

The border will be down the Irish sea, he said. And while his company won't be doing them, it will have to provide room for officials to do the checks, he said.

As well as operating a fleet of ferries connecting Great Britain to the island of Ireland, Stena also owns three ports on the route, and wants to know the physical changes required on what has, until now, been seamless trade.

The industry's assumption is that the checks will be done in Great Britain on exit rather than in Ireland or Northern Ireland.

For much more on trading relationships including those on the North Channel routes click here.