A key player in Britain’s first involvement in the European Union has called for a second Brexit referendum, after attending his first protest march at the age of 91.

Uwe Kitzinger worked as an adviser to Winston Churchill’s son-in-law, Christopher Soames, from 1973 to 1975, when Lord Soames became the first British vice-president of the European Commission.

Mr Kitzinger attended the People’s Vote march in London on Saturday, and afterwards told the PA news agency that the public were now better informed to make a choice.

Uwe Kitzinger attends the People's Vote March in London
Uwe Kitzinger attended the People’s Vote march in London on Saturday (@RosiePhippsArt/Twitter)

“I do not see how the question of sovereignty over the issue of Europe can be settled without the people of this country having a say, now that they are much better informed, and now that there is actually a proposal,” Mr Kitzinger said.

“We now see the beginnings of a transition to a destination, but it’s very clear that the destination is meant to be one of national tribalism, and that is the beginning of the kind of international tensions which can so easily lead to war.

“It is the negation of all I stood for and all I worked for in my career, but that isn’t the important thing.

“The important thing is what happens to my grandchildren, and their children.”

As well as having worked for Lord Soames, Mr Kitzinger served as the first British economist of the Council of Europe in Strasbourg – he also wrote books urging Britain to join the European Economic Community.

The former president of the Oxford Union travelled from Oxford to London to attend the People’s Vote march with friends and family, and described the scene on the streets as “a festival atmosphere… a joyous atmosphere.”

The People's Vote march in London
The People’s Vote march in London (Victoria Jones/PA)

Fundamentally though, Mr Kitzinger made his feelings about Brexit clear, and took aim at a number of world leaders, including Boris Johnson.

“I see Brexit as a blow against the cohesion of the world,” he said.

“All the institutions that were set up at the end of the Second World War – the World Bank, the United Nations itself – all these are under attack from Mr (Vladimir) Putin, and from him through Mr (Donald) Trump, and our present so-called prime minister.

“I have had a lifelong conviction that it matters desperately, if we want to keep peace and attain a wider prosperity in the world, for nations to pull together, not to pull each other apart.”