Former deputy PM says he urged rethink of remain strategy as it was failing to compete with emotional pull of leave campaign

Nick Clegg has revealed he urged David Cameron to change the remain campaign strategy in the final weeks before the EU referendum, saying the economic-focused Stronger In campaign was “bloodless” and failing against the emotional pull of the leave campaign.

In an interview with the Guardian’s Owen Jones, the former deputy prime minister said he believed voters in Sheffield, where he has his constituency, had wanted to send a message not just to Brussels but to southern England and London for leaving the north of the country behind.

“For a lot of people it was a vote against London, ‘them down there’,” the former Liberal Democrat leader said. “I got in touch with David Cameron by email and I said, ‘I think the emotional case for remain is being lost’. And my suggestion for the last week of the campaign was to do proper battle with the very emotionally pungent Brexit slogan, ‘Take Back Control’.

“I said why not, ‘Vote remain to keep us safe’, so safe from recession, keep our kids safe etc? I just thought it was more emotionally powerful. He politely replied he wanted to stick to the economic strategy.”

Clegg said he did not blame Cameron for the loss of the Brexit vote, but said the campaign was “very bloodless and allowed a more emotionally impactful argument in favour of dollops of money for the NHS, and economic utopia, the traffic would flow, the sun would shine, it allowed the other side to make these ludicrous claims … in a relatively unchallenged way”.

The MP, who worked at the European commission before entering frontline politics, has drawn up a proposal for an interim deal for the UK after it formally exits the EU, which would involve re-entering the European Free Trade Area (Efta), which the UK spearheaded almost 60 years ago.

Now comprising only four members – Norway, Iceland, Liechtenstein and Switzerland – it would mean the UK remained inside the single market but outside the customs union and other schemes such as the common agricultural or common fisheries policies.

The prime minister, Theresa May, is due to confirm the UK will be leaving the single market, with 12 key priorities for negotiations including control over immigration and removing Britain from the jurisdiction of the European court of justice.

Clegg said he believed it was a dereliction for the prime minister to pursue a hard Brexit strategy. “If you are the prime minister of such a deeply divided country, you have a duty to find a compromise, it means maybe some changes to how immigration works, trying to preserve our place in the single market,” he said.

“It doesn’t mean unilaterally getting rid of everything and delegitimising the aims and hopes and dreams of 48% of the voting public. Since when does a prime minister basically say that the needs and aspirations and interests of 16.1 million fellow citizens counts for nothing?”