FOR the record, I rather like David Mundell, our current Secretary of State. Of course, he is the only Tory MP elected in Scotland, so the Westminster government hasn’t a lot of choice. But David is a personable, non-sectarian chap who has devoted himself to using Dover House, the magnificent 18th-century pile in Whitehall that is home to the Scotland Office, as the de facto Scottish Embassy in London.

This is welcome news as before the 2015 General Election, Dover House had been commandeered by the sanctimonious Nick Clegg as his Deputy PM’s office. With Clegg now a distant memory, this one-time residence of the French ambassador is the setting for a constant round of events for visiting Scottish businesses and charities – to which all MPs north of the Border are invited. Which means these diplomatic soirées are dominated by the SNP contingent, whose offices are just across the street. When the time comes, Dover House will make a very nice base for the real Scottish ambassador to the Court of St James.

David Mundell’s problems begin when he ventures into politics, as he did last week over Scotland’s relationship with the European Union. David was the very first Cabinet minister to come out for remaining in the EU – a view shared by the vast majority of Scots. But having been reappointed to Dover House by our new, unelected Prime Minister, he has seen fit to jump on the “Brexit means Brexit” bandwagon. In a speech marking the anniversary of the 2014 independence referendum, our David turned his guns on the SNP for seeking to defend the majority will of the Scottish people to stay in Europe. Sadly, David could only dip into the musty box of Tory Brexit platitudes and downright fibs to justify his change of heart. First, he brought up the old canard that if an independent Scotland stayed in the EU, there would have to be border posts along Hadrian’s Wall.

“The only way to guarantee an open border between England and Scotland is to stay part of the same Union,” quoth our Secretary of State, forgetting that David Davis, the man in charge of the UK’s Brexit negotiations, has already been to Northern Ireland to assure its citizens there won’t be a “hard border” with the Irish Republic. Just to be sure, I got Mr Davis to repeat that guarantee in Parliament. So why would Scotland – either independent or still part of the UK but inside the EU single market – require different border arrangements than Northern Ireland, David?

However, our Secretary of State was not finished blundering about. He went on to inform us that an independent Scotland would – if allowed – have to join the EU on much more onerous terms than the UK has at present. For instance, he mused, Scotland would not benefit from Britain’s current rebate on EU membership contributions – implying Scots would pay more per head than today as continuing members of the Union. Ding! Ding! Reality check! Here our David is indulging in the statistical jiggery-pokery the Brexiteers used to bamboozle the British electorate. Here’s how I know.

Last week I joined a number of colleagues on the Treasury Select Committee on a fact-finding visit to Berlin and Rome, to take soundings on how the EU would approach a Brexit deal with the UK. I also used the opportunity to put the case of the Scottish Government for a separate deal for Scotland – while remaining a part of the UK – to continue to access the EU single market with free movement in goods, services, capital and people.

In Berlin, our meetings included a senior German finance minister, the leading spokesperson for the German car industry, MPs from our equivalent committee in the Bundestag, prominent representatives of the banking world and chambers of commerce, and a close personal political confident of Chancellor Merkel. In Rome, we met with the Bank of Italy, senior civil servants at the Finance Ministry, the chief economic advisor to the prime minister, leading opposition MPs, senior bankers and a recent former finance minister. That’s more diplomacy than David Davis has managed.

Everywhere we went we got the same story: the UK has to make up its mind what relationship it wants with the EU – membership of the single market like Norway and Switzerland, a customs union, a unique free trade deal, or minimum World Trade Organisation rules. Only then will Europe negotiate. Even then, expect no favours. As far as most of the Germans were concerned, their first concern is to stop the UK Brexit vote destabilising the rest of the EU. Britain could not get a special deal in immigration because it would lead inevitably to other members demanding similar treatment. Chancellor Merkel would avoid this like the plague. Politics would trump economics, even if Germany does have a trade surplus with the UK.

As a result, if soft Brexiteers like Theresa May and David Mundell are angling for continued membership of the single market, they will have to pay for it. The UK can have a similar deal to Norway and Switzerland, but it would have to accept EU rules without the right to determine them. And the UK would still have to pay its contribution to EU solidarity funds. Sorry David: expect these contributions to be the full whack, without the current UK rebate; ie, expect a post-Brexit UK inside the single market to end up paying more per head for the privilege.

None of this surprised me. What did was the fact that everywhere we went, in Berlin and Rome, there was already an appreciation that Scotland had voted to stay in the EU – and that this might trigger a second independence referendum. One German banker (who knew Edinburgh well) left the rest of my group speechless when he opined that most ordinary Germans would gladly agree to Scotland staying a member. A very senior official at the Italian central bank came up to me smiling after our meeting to say: “We are all curious as to what Scotland will do”.

We need to give our friends in Europe an answer to that question. In the uncertainty resulting from the political vacuum at Westminster, Scotland “inside the UK” has to press its European case in forensic detail, in concert with the Scottish business and financial community. We need a united deal that keeps Scotland, Northern Ireland and Gibraltar inside the single market and the EU customs union. Negotiations for such a deal have to be real and not a political manoeuvre, lest we lose the confidence of business. But if, as I fear, the Brexit ultras in the Tory Party force Mrs May to take the UK out of the single market as well as out of the EU, then Scotland needs to have a detailed blueprint for what happens next.

England’s exit from the EU is likely to end in a messy divorce. A second but successful independence referendum is not the end of the matter: we need our own roadmap to stay in Europe. After all, we could be the only EU member state with an embassy at the heart of Whitehall.