The European Union is an explicit political project designed by a former communist, Iain Duncan Smith has said.

The Work and Pensions Secretary, a eurosceptic, said it was important for the British public to realise that the EU was not about trade – but political integration.

He highlighted the contribution of Altiero Spinelli, a political theorist and former European Commissioner, to the founding to the EU.

“It’s worth knowing something here that the public needs to understand … the European Union is not about the trade issue,” Mr Duncan Smith told BBC One’s Andrew Marr Show.

“The EU was set up by the founding fathers, an important man called [Altiero] Spinelli, an Italian, who was an ex-communist, he designed the Maastricht Treaty and the Single European Act, why?

“He said because this is a political project, bringing the nations of Europe closer and closer together to create a place called Europe and the design of this was such that politicians who come and go could not actually override this decisions of the bureaucracy because otherwise we would never get there.”

The late Mr Spinelli is one of 11 officially recognised founding fathers of the European Union; other include former British Prime Minister Winston Churchill, who called for the creation of a United States of Europe.

The Italian politician joined the Italian Communist Party in the 1920s to fight Benito Mussolini’s fascist dictatorship, which ruled Italy at the time.

What has the EU ever done for us? Show all 7 1 /7 What has the EU ever done for us? What has the EU ever done for us? 1. It gives you freedom to live, work and retire anywhere in Europe As a member of the EU, UK citizens benefit from freedom of movement across the continent. Considered one of the so-called four pillars of the European Union, this freedom allows all EU citizens to live, work and travel in other member states. What has the EU ever done for us? 2. It sustains millions of jobs A report by the Centre for Economics and Business Research, released in October 2015, suggested 3.1 million British jobs were linked to the UK’s exports to the EU. What has the EU ever done for us? 3. Your holiday is much easier - and safer Freedom to travel is one of the most exercised benefits of EU membership, with Britons having made 31 million visits to the EU in 2014 alone. But a lot of the benefits of being an EU citizen are either taken for granted or go unnoticed. What has the EU ever done for us? 4. It means you're less likely to get ripped off Consumer protection is a key benefit of the EU’s single market, and ensures members of the British public receive equal consumer rights when shopping anywhere in Europe. What has the EU ever done for us? 5. It offers greater protection from terrorists, paedophiles, people traffickers and cyber-crime Another example of a lesser-known advantage of EU membership is the benefit of cross-country coordination and cooperation in the fight against crime. What has the EU ever done for us? 6. Our businesses depend on it According to 71% of all members of the Confederation of British Influence (CBI), and 67 per cent of small and medium-sized enterprises (SMEs), the EU has had an overall positive impact on their business. What has the EU ever done for us? 7. We have greater influence Robin Niblett, Director of think-tank Chatham House, stated in a report published last year: “For a mid-sized country like the UK, which will never again be economically dominant either globally or regionally, and whose diplomatic and military resources are declining in relative terms, being a major player in a strong regional institution can offer a critical lever for international influence.

He spent over a decade as a political prisoner and went on to become one of the leading lights of European Federalism.

Mr Spinelli died in 1986, seven years before the actual creation of the European Union. A version of a plan he proposed for European integration was backed by the European Parliament in 1984 and is regarded by the EU as "inspiration" for the treaties.

Mr Duncan Smith, who is campaigning to leave the European Union, insisted Britain would be able to secure full access to the single market and border controls outside the European Union.

He accused David Cameron and George Osborne of having a “low opinion of the British people” because of their pronouncements about what would happen if Britain left the EU.