“For us in Kosovo, we would like to see Britain in the European Union – definitely the EU cannot be the same without Britain,” says Hashim Thaci, the country’s president. “We cannot continue to pretend that nothing has changed, nothing is happening, this is a very, very big thing.”

He stresses: “Without Britain, the European Union will lose a lot of substance. It is not a good situation, for the EU or for us in Kosovo.”

The president was speaking about these troubled times from the viewpoint of his part of the continent. He is on a rocky road to ensuring that there is not a return to the Balkan wars – a conflict of death, atrocities, mass rapes and ethnic cleansing. The violence shocked Europe, which thought such savage strife was stuff of the past.

Now the former adversaries, Serbia and Kosovo, are being urged by the west to draw a line under a simmering feud that has threatened to reignite.

The leaders of the two states – Thaci and Aleksandar Vucic – both viewed in the past as fiercely unbending nationalists, have held talks, most recently at the annual Munich Security Conference. Another round of negotiations is expected to be held in the near future.

There is a general agreement from both sides that membership of the European Union is pivotal to achieving long-term peace and, in the case of Kosovo, joining Nato too.

“The circumstances we face in Kosovo, the only future, the only way forward, is membership of the European Union, there is no doubt about that,” maintained Thaci during a visit to London.

“As Kosovo we will do all our duties, tasks, to deserve to be a Nato member and an EU member. We want eventually to see open borders within the EU, with Albania, Macedonia, Montenegro and Serbia, everywhere in the region. Regarding Nato, I think we are talking about a five to 10 year time frame, or perhaps even less, to join.”

Sitting in the breakfast room of a hotel in Kensington, Thaci looks relaxed and urbane in a white and blue checked shirt and jeans. He was in combat fatigues the first time I met him, 20 years ago, drained and pale after a difficult military operation by the Kosovo Liberation Army (KLA), which he led at the time.

Britain will always remain a partner for Kosovo, whether it is a member or not. It was a key contributor to freedom and independence of Kosovo Hashim Thaci, president of Kosovo

It was a time of ferocious fighting in Kosovo, and Nato bombing of Serbia, amid bitter recriminations between Russia and the west.

Nato’s Kosovo Force (KFOR) headed by British Major General Mike Jackson, went into Kosovo, while Moscow sent in their own military contingent. Both sides were racing to secure the airport in the capital, Pristina, and the strategic advantage that went with it.

There was a tense standoff, which I and other journalists witnessed in an evening of stormy rain, during which Jackson refused the order from his superior, the American General Wesley Clark, to block the runway to the Russians. Jackson’s response is now part of the history of the conflict: “I am not going to start the Third World War for you.”

Jackson had his way and a potentially incendiary confrontation was averted after the dispute reached the White House and Downing Street. They backed the British General over Clark, who was the Supreme Allied Commander Europe (Saceur).

The Russians landed their flights, their troops went on a few symbolic joint patrols with Nato troops, and then withdrew. General Sir Mike Jackson went on to become the head of the British Army.

Thaci had dinner with Jackson a few evenings before our meeting. “It was good to catch up and talk about old times – but also what’s going on now,” he says.

“Britain will always remain a partner for Kosovo, whether it is a member or not. It was a key contributor to freedom and independence of Kosovo and we will always be grateful for this.”

The Balkan wars led to bitter divisions within Europe, with countries taking sides as Yugoslavia was dismembered: one example of the acrimony was that early German recognition of Croatian independence was widely portrayed as payback for the support given to Germany by the Ustashe during the Second World War.

Sceptics have been saying that Trump would not care about the Balkans. In fact he has been very attentive, very supportive Hashim Thaci

A number of EU member states – Greece, Spain, Romania and Cyprus – have yet to recognise Kosovar independence. Thaci says: “There is disunity among some EU members on some things as we know, and there is disunity over Kosovo as well. International unity would really help with the dialogue we need to achieve an agreement (with Serbia). No doubt it would speed up the process.”

Donald Trump has, rather unexpectedly, taken an interest in the issue, urging both sides to continue negotiating. “Sceptics have been saying that Trump would not care about the Balkans,” says Thaci. “In fact he has been very attentive, very supportive, but really he was following the policies of other presidents over Kosovo and the Balkans, Bush senior and junior, Clinton and Obama. Trump has sent two letters in two months, both to me and President Vucic of Serbia, with a very clear message to reach an agreement this year.”

While Thaci was leading the KLA in Kosovo, and Nato warplanes were over Serbia, Vucic was minister for information in the government of Slobodan Milosevic in Belgrade, railing against what he saw as victimisation of the Serbs by the west. He was also consumed by what the regime saw as “treachery within”, bringing in the draconian “Vucic law” to muzzle opposition media.

Vucic is now viewed as a man the west can do business with and has been credited with reforming Serbian politics. He is facing some internal opposition, but was seen, for a long time, as the power-broker in his country. He remains the most influential politician.

Serbian President Aleksandar Vucic says Albanians 'didn't want to compromise' over Kosovo army

I recall a dinner Vucic, then deputy prime minister, hosted six years ago in Belgrade for a small group of journalists on a day the Serbian government fell.

He made a series of calls on his mobile phone in between courses, and, highly impressively in our view, had formed a new coalition administration by the end of the meal.

“Mr Vucic definitely has changed, mainly because he has gone through difficult times because of his own mistakes,” says Thaci. “The regime he belonged to once was evil, a regime that did a lot of harm not only to Kosovo, Bosnia and Croatia, but even to Serbia itself.”

“In 1998 and ’99, Vucic and I were in opposition. We won, he lost. Nevertheless, he is a legitimate leader, in Kosovo and Serbia, leaders that were voted by the citizens. We have all changed in a positive way, we’ve had to evolve. Now we don’t speak of war and conflict but speak of how to reach peace. There have been recent demonstrations in Serbia, and there is a danger they might scare Vucic away from reaching an agreement, but we hope not. Unfortunately, there will always be those who are opposed to peace.

“Vucic is a very difficult person to negotiate with, to have dialogue with. But I did not choose him as my counterpart, he didn’t choose me as his own counterpart, it’s the reality of these two sovereign countries.”

Thaci faces his own problems. The Kosovo Specialist Chambers and Specialist Prosecutor’s Office, set up in the Hague in 2017, is investigating allegations of war crimes against a number of senior figures in the KLA, including the Kosovar president.

Thaci insists he has nothing to fear. “As always, we will not run away, we will not shy away, we will face it and I am convinced we will overcome it with dignity and integrity,” he says.

“I am personally very proud that I was one of the leaders of the Kosovo Liberation Army. There will always be voices that try to denigrate Kosovo or accuse Kosovo, smear Kosovo and me personally. But this doesn’t mean that I have any hesitation on what’s our way forward and how we should proceed forward. I believe in justice. What we should not allow to happen is for the history to be rewritten.”

Of course the biggest hurdle is the past. But I think now really is our turn to reach a peace agreement Hashim Thaci

The Kosovar president accuses the international community of double standards: “We still didn’t even see trials, convictions for the genocide in Serbia carried out in Kosovo. And for us, it is a matter of concern, this silence of the international community towards these crimes. We have had as many as 15,000 civilians killed. Up to 20,000, it’s estimated, victims of sexual violence. There were around 200 massacres against civilians in Kosovo, all around Kosovo. International justice has failed to convict those responsible for these crimes.”

But Thaci is also very aware of the burden of history in the Balkans.

“Of course the biggest hurdle is the past, ” he says. “But if we look now broadly at the region, in particular after the recent agreement between Macedonia and Greece, the main issue, I think now really is our turn, Kosovo and Serbia, to reach a peace agreement. After all, dialogue has no alternative. It’s the only solution.”