In an interview with the Sunday Telegraph, the prime minister said he had defied accusations of “cake-ism” – seeking the impossible – in getting a trade deal that allowed divergence from EU standards.

It had been, Johnson said, billed as out of the question “that you could do free trade with the EU without being drawn into their regulatory or legislative orbit”.

While service industries, the bulk of UK exports to the EU, could face potential regulatory or other non-tariff barriers, Johnson said there had been “access for solicitors, barristers” and a “good deal for digital”.

But on financial services, he said the deal “perhaps does not go as far as we would like”.

There are measures in the agreement for the possible imposition of tariffs if the UK diverges notably from existing standards. Johnson said this should not be viewed by Brexit-minded Conservative MPs as too restrictive.

“All that’s really saying is the UK won’t immediately send children up chimneys or pour raw sewage all over its beaches,” he said. “We’re not going to regress, and you’d expect that.”

Saying it was “unlikely” the UK would impose its own tariffs, Johnson added that any imposed by the EU “would have to be proportionate and approved by the arbitrator”, and if that happened regularly, the UK would revert to World Trade Organization trading terms.

However, Johnson told the paper, the UK could and would set its own path in some areas, mentioning as one idea the notion of so-called free ports, low-tax trade zones which advocates say boost economic growth, but which have been accused of helping tax evasion. Free ports exist within the EU, although with some restrictions.

The prime minister said more plans would emerge now the trade deal was finalised: “A great government effort has gone into compiling these and we haven’t necessarily wanted to talk about them much during this period because that perhaps would not have been fruitful.”

He added: “We want to see what we can take forward. We don’t want to diverge for the sake of diverging. But we’re going to want to do things differently where that’s useful for the British people.”

MPs and peers will gather on 30 December to scrutinise and vote on the deal, before the 1 January expiry of the current Brexit transition period.

While the fact Labour has said it will vote for the deal guarantees it will pass easily, Johnson could still face anger from the strongly pro-Brexit wing of his party, who are currently examining the details of the agreement.

In the interview, Johnson sought to portray the deal as the ultimate conclusion of Margaret Thatcher’s 1988 speech in Bruges, in which she railed against the idea of a “European superstate”, calling Thatcher’s address “prophetic”.

“It’s the end of a long and fractious period, in which we kept trying to pretend to ourselves that we could go along with all sorts of things we didn’t really want to do for the sake of keeping up with the great project of European Union,” he said of the trade deal.

“I think this gives us a basis for a new friendship and partnership that should attract people who love Europe and want to have a great relationship with it, who want to feel close to it.

“But it should also be something that is welcome to people who see the advantages of economic and political independence. I think the country as a whole has got itself into a new and more stable footing. It’s a better relationship and a healthier relationship.”