THE challenge facing Theresa May in securing her Brexit goals was underlined by reaction from the bloc of 27 EU nations she must negotiate with over the next two years.

Although there was a welcome for “clarity” on what is seen as a hard Brexit, there was also unhappiness at the threat to undercut the rest of the EU on tax if Mrs May did not get her way.

Many governments also pointed out Mrs May’s statement was an opening gambit in talks which had yet to start, and which would not do so until she triggers Article 50 in March.

Read more: Nicola Sturgeon warns Theresa May that hard-Brexit means second independence referendum all but inevitable

Guy Verhofstadt, the European Parliament's Brexit negotiator, said it was an “illusion" to think the UK could enjoy the benefits of the EU single market without accepting its obligations.

The EU would not accept a deal that was better for Britain than EU membership, he said.

Mrs May’s suggestion "that you can go out of the single market, that you can go out of the customs union and that you can cherry-pick, that you can have still a number of advantages - I think that will not happen,” he said.

Michel Barnier, the EU’s chief Brexit negotiator, said his priority was “to get the right deal for the EU27”, and said an orderly exit was a “prerequisite for future partnership”.

The Czech Europe minister Tomas Prouza called the UK’s plan “bit ambitious - trade as free as possible, full control on immigration...where is the give for all the take?”

Sweden’s former prime minister Carl Bildt said: "I regret the approach the UK government has taken. I think most of the EU would have preferred a closer relationship with the UK."

Read more: Nicola Sturgeon warns Theresa May that hard-Brexit means second independence referendum all but inevitable

Polish Europe minister Konrad Szyma?ski said: “On the future of movement of people we respect that UK wants to control migration, but any scheme must be proportionate and ensure fair treatment of all EU citizens regardless their professional profiles.”

German Green MEP Jan-Philipp Albrecht posted, then deleted, a tweet suggesting Mrs May’s attitude was “Go f*** yourself EU, but please don’t let us down. *whine* whine*.”

He added: “Many of the 52 per cent of Brits voting leave clearly believed that they would stay in a common European market. They’re f***ed together with the 48 per cent.”

However Donald Tusk, the president of the EU Council, said Mrs May’s speech had given the EU a “more realistic” view of UK intentions, but stressed the EU27 were united .

In a wistful tweet, he said: “Sad process, surrealistic times but at least more realistic announcement on Brexit. EU27 united and ready to negotiate after Article 50.”

Germany’s foreign minister, Frank-Walter Steinmeier, said the speech had “finally” given the rest of Europe “a little bit more clarity” about the British plans.

He said the EU27 wanted "good, close and trusting relations" with the UK and would, like Britain, aim for constructive negotiations.

Chancellor Angela Merkel is due to discuss Brexit with her ministers today.

Read more: Nicola Sturgeon warns Theresa May that hard-Brexit means second independence referendum all but inevitable

Florian Philippot, vice-president of Marine Le Pen's far-right National Front in France: "Bravo to T. May who respects her people with a 'clear and clean' Brexit. Sovereignty cannot be a half-measure. French independence soon!”

The unpredictable nature of the talks is compounded by elections in France, Germany and the Netherlands in 2017, which could see a change in governments and priorities.

This also complicates makes Nicola Sturgeon’s decision on holding a second referendum, as her basis for doing so - the nature of the final Brexit deal - is likely to remain unclear until late 2018, when Brexit will have almost arrived.