Jeremy Hunt has said the European Union has taken a more constructive approach to Brexit since he compared the bloc to the Soviet Union.

Last month, the foreign secretary told delegates at the Conservative party conference that the EU wanted to punish a member state for leaving, and likened its tactics to Moscow’s during the Soviet era. When asked on Friday whether he regretted the remarks, which were widely criticised by EU officials, Hunt implied they had had a positive effect.

Speaking to BBC Radio 4’s Today programme, he said: “It was a very passionate argument that said the EU was set up to defend our freedoms against totalitarianism so it was not appropriate for a club of free nations to take the attitude that someone that leaves should be punished.

“In the period since that speech we have had a very different approach from the EU, a much more constructive approach that has led to the situation we’re in now where all but one or two issues have been resolved.”

Hunt said “the only big outstanding issue” to remain unresolved was the Irish border, adding Theresa May had held firm and stuck to her principles with regards the Northern Ireland backstop. “We will not agree to indefinite membership of the customs union and we won’t agree to the carving up of the UK,” he said.

He said compromises would have to be made. Following tense talks in Brussels this week, the prime minister suggested the UK may have to stay tied to EU rules and laws beyond December 2020, prompting a furious backlash from Conservative backbenchers.

Hunt said: “There is a situation in which you’ve negotiated a free trade agreement and it’s going to take a few months more to implement, but months not years, when it might be helpful to have the ability to extend the transition period.

“There’s all sorts of difficulties and all sorts of compromises that people of all sides are making, but the fundamental point is that we are leaving the EU at the end of March next year and we’re leaving it with the letter and spirit of what people voted for in the referendum.

“In that context of us winning those big battles, of course there are gonna be things that we decide to do to create stability for business, for example.”

Hunt called on Tory party members to rally behind May as she worked towards bringing what he described as a viable deal to parliament. “The great strength of the EU in these negotiation is that the 27 EU nations have remained united and now we need to do the same behind Theresa May,” he said.