The unexpected decision of Britain to leave the European Union needs to be handled with calm on both sides. The British are struggling to organise themselves but need to move quickly to start talks with Brussels about how to start the process, even at an informal level.

The European Union would do well to try and find as smooth a way forward as possible, because anger at the British decision and a desire for revenge will only create more uncertainty that will be damaging to all sides.

The tone set last Friday by both the presidents of the European Parliament and European Commission was overly aggressive. They suggested that the EU did not need to wait on the convenience of the British Conservative Party to start the departure negotiations, and that they were looking at how the EU could trigger Article 50 immediately rather than wait for the British to sort themselves out.

Brussels may well feel that a whole continent cannot be taken hostage because of an internal fight in the Tory party, but both sides need to make Britain’s departure as smooth as possible.

It is true that the EU needs to move on but it can do that while also sorting out the British issue. Now that all the EU member states know that the UK is no longer relevant to their planning, they can address several urgent issues in their own way.

A primary concern is that the EU needs to sort out its economic malaise and find a way to become more competitive, while also strengthening the euro.

At the same time it is also wrestling with the huge numbers of refugees in the Mediterranean. And it is trying to find a way to co-exist with a nationalist Russia seeking to overturn the post-Cold War order. The surviving 27 EU member states will have to plan for these issues while simply ignoring Britain.

Even if Britain is still a member of the EU, it will cease to have any influence and will become rapidly marginalised. For example, several officials last Friday in Brussels were querying if the British commissioner in charge of financial affairs should not be shunted out to become a commissioner without portfolio while Britain remains a member. Prime Minister David Cameron may turn up at the summits, but will have nothing to contribute.

But irrelevance should not tip into anger and the departure talks should be attempted with goodwill.