The official Remain campaign, known as Britain Stronger In Europe, has relaunched as a campaign group called Open Britain, but has stopped short of calling for a second referendum, and says controls on free movement of people should form part of Britain’s renegotiated arrangements with the European Union.

Open Britain will campaign to ensure that the UK is seen as outward looking and open for business with the rest of the world, but accepts that the result of the referendum should be final.

The group's supporters include former ministers Anna Soubry from the Conservative Party, Liberal Democrat Norman Lamb and Labour's Pat McFadden.

In a joint article in the Sunday Times, the three acknowledged the Brexit vote had been driven by concerns over immigration but argued the UK could not cut itself off from the world.

They said: "June 23 was a moment of change. The strength of feeling is clear. Free movement of people cannot continue as it has done. It has to be reformed.

"This was not an expression of prejudice but rather a desire for managed migration and concern that rapid immigration can put pressure on public services and local communities.

"Britain must be open to talent, but with more ability to act if excessive competition in labour markets hurts our economy."

They added: "Calls for reform must sit with a positive argument about the benefits that immigration brings.

"If we interpret the referendum result as a vote for a more insular and less inclusive country, or one in which the only way to advance working people's living standards is to turn our face against the world, we will have converted a defeat into a tragedy."

In a message aimed at the Brexit camp's desire to leave the European single market, the ex-ministers said: "For an open Britain to be a fairer Britain we must reject false choices, whether between being open to the world and remaining in the EU's single market; whether between a competitive economy and protections for workers and consumers; between being open to talent and having greater control over immigration; or between embracing change and valuing tradition."