“Heavy Fog in the Channel. Continent cut off.” That was the headline in The Times on 22 October, 1957, when air and sea traffic in the English Channel was temporarily shut down. To the British, this wasn’t unfortunate because it cut Britain off from Europe – but because it cut Europe off from Britain.

Since then this headline has been used many times to depict the UK’s relations with the EU. And while British voters and politicians have always seemed more Eurosceptic than their continental partners, that fog has only thickened since 2010.

First there was David Cameron’s commitment to hold a referendum on new EU powers. Then his attempt to block Jean-Claude Juncker from becoming president of the European Commission. And now Britain is discussing whether or not to leave the EU altogether, with voters split 50/50 in favour and against.

The Conservatives have been especially critical about economic and financial policy. The UK has fought against a range of EU crisis management measures, “vetoing” the Fiscal Compact on eurozone budget discipline in December 2011 and resisting the provision of more funds to the International Monetary Fund for euro bailouts.

These actions challenge the Council of the EU’s strong unwritten rule of consensual decision-making. And that raises an interesting question: what happens when someone challenges, or even flouts, the rule? Are their diplomats marginalised, or do other countries make an extra effort to attempt to get them on board?

In a newly published article, I’ve examined what impact the British government’s stance has had on its diplomats’ relations with their counterparts in Brussels. Based on 33 interviews with diplomats from 20 countries, I found that Britain is not yet completely marginalised.

Being an awkward partner doesn’t automatically lead to being left out in the cold: other negotiation qualities, such as being skilful and informed, are just as important. And anyway, Britain is simply too big to be excluded from informal meetings.

Moreover, there is a strong belief in the EU that even the most obstinate members should be listened to and their concerns understood. Most people I spoke to saw it as inappropriate and unfair to simply exclude a “recalcitrant” country from informal meetings.

That’s the good news. But it’s all downhill from here.

The overwhelming sense I received from the diplomats I spoke to was that Britain has isolated itself in the EU.

One reason for this was practical: several interviewees said British diplomats and officials have become less engaged over the years, writing fewer discussion papers and failing to join in the process of finding solutions.

But the other reasons go deeper. Most interviewees believed that the UK persistently took up an extreme and immovable position that was not constructive. This, they said, had left the UK unable to influence the EU’s legislative process as much as it would like.

This has produced a certain element of fatigue when it comes to accommodating British concerns. Other countries are less willing to go the extra mile to get the UK on board. There was a clear sense among interviewees that the it acts in a way that goes against EU norms of alliance-building and compromise.

Several Northern European countries, such as Denmark, the Netherlands and Sweden, regretted that the UK has isolated itself because they see it as an important partner. At the same time they were unwilling to coordinate their positions with the UK at any price.

That isolation is so advanced that many diplomats saw the act of aligning oneself with the UK as dangerous. To do so, they said, is to go against the EU spirit, breaching community norms and alienating other countries.

Previously, one Danish diplomat told me, “it was more legitimate to be seen to share views with the UK. Now we do not want to be in the same boat as them.”

An official from the Council put it even more bluntly: “Even the best idea can die if it’s presented by the UK.”

This concern about being associated with the UK is particularly prevalent in areas where the UK takes a “stubborn and immovable” position.

Several interviewees mentioned that they were more reluctant to engage in coalitions with the UK, particularly if it was likely to end up as a minority coalition. By contrast, they did not see it as dangerous to be left in a minority coalition with other big countries. This was all about the fear of alienating other countries by aligning with the UK.

The biggest fault lines were between Britain and the EU institutions, Britain and the Nordic countries, and Britain and Poland.

Many interviewees said there had been a change in how MEPs and European Commission officials perceive the UK. One British diplomat said: “MEPs think the UK will throw a spanner in the works. The Commission hates that we do not believe in the EU project.”

UK diplomats are finding it particularly difficult to influence the European People’s Party (EPP) and the Socialists and Democrats (S&D) when it comes to the “big stuff” – such as bankers’ bonuses, on which they feel Britain is regarded as a “financial bogeyman”.

Meanwhile, Polish diplomats said that they felt somewhat betrayed by the UK because the UK had played a key role during Poland’s enlargement negotiations with the EU.

Now that Poland is in the EU, it feels as if it has “lost a friend”, as one Polish diplomat put it.

Similarly, countries who don’t use the euro feel that they have lost an important ally in their “fight” against gradual marginalisation in the EU.

So while the UK hasn’t yet been completely cut off from the continent, the fog is thickening.

This piece is by Maja Kluger Rasmussen, public policy analyst at the independent Danish think tank, Think Tank Europa, was co-published with The Telegraph.