There is no economic case for remaining a member of the European Union, former chancellor Lord Lawson has insisted.

The Tory peer, chairman of the Vote Leave campaign, said the EU was a "political and not an economic enterprise" and claimed the UK would be able to negotiate a trade deal which would exempt it from Brussels' free movement rules and membership contributions.

He said the referendum on June 23 could mark the date of "Britain's declaration of independence".

Lord Lawson said David Cameron's negotiations had failed to achieve meaningful changes to the UK's relationship with Brussels during the "charade of a negotiation".

In a speech at the Royal Institute of International Affairs in central London, he said the EU was "not only wholly unreformed, it has proven itself to be unreformable".

He said: "We remain unwilling passengers in a car driven by others to a destination which we vehemently wish not to reach."

The peer, who was Margaret Thatcher's chancellor, said "the answer has to be that there is no economic case" for continued membership.

"The EU with its single market is the slowest-growing economic bloc in the world and there is no reason to believe this is going to change.

"This is partly because of the dysfunctional single currency and partly because of the deep-seated unwillingness to undertake the sort of structural reforms which we in this country put in place during the Thatcher era."

EU red tape hit all firms in the UK, including the 85% which did not export to the continent, he added.

He asserted that the rest of the EU would negotiate a free trade agreement with the UK after Brexit because of the demand for goods and services from British consumers.

Tariff-free access to the single market was "desirable but it is by no means essential", he said.

"The EU's common external tariff has a weighted average of somewhere between 3% and 4%, which is hardly a massive burden. However, it is implausible in the extreme that we would not be able to negotiate a free trade agreement once outside.

"Germany, for one, will insist on it - not least the powerful German motor industry for whom the UK is far and away their largest export market."

The former chancellor said that "free trade agreements are about trade - usually they include free capital movement, they do not include population movement".

Insisting that the UK would not adopt the Norwegian model, which sees Oslo pay in to Brussels' coffers for access to the single market, he said there was "no need" for that.

"They need our money more than we need theirs," he said.

He dismissed the warning from leading businesses against a vote to leave, insisting that as many major firms had warned of economic disaster if the UK did not adopt the euro, "I don't think their track record is all that great".

Lord Lawson condemned Foreign Secretary Philip Hammond's "rather shameful" attempt to scare British people by saying "if we leave, our former partners will try to punish us - there is no legal way in which they can do this, more importantly it wouldn't be in their interest to do so".

"If we were to vote to remain in the EU, then they would indeed be able to punish us and it may well be in their interest to do so. There is seldom gratitude in politics."

Addressing the "democratic deficit" in Brussels, Lord Lawson added: "Membership of the EU, however well intentioned, is an affront to self government and offers nothing that remotely compensates for this."