The Conservative party are not liked or trusted by voters who see them as “aliens from another planet” a Conservative minister said in a shock admission yesterday.

Tory planning minister Nick Boles said the party’s toxic image meant that large numbers of voters “will literally not even contemplate voting Conservative”.

Boles who was once a key figure in David Cameron’s plans to modernise the party’s image, told a meeting in Westminster not enough had been done to convince voters the party has their best interests at heart.

“The single biggest problem the Conservative party faces is being seen as the party of the rich,” he told the Bright Blue discussion group.

“I don’t think we have done enough to reassure people about the motives behind economic liberation, that we genuinely believe that you will get better health services or housing or whatever, rather than that our mates who work for private equity will make a ton of money. We have not eradicated that suspicion.”

While people may agree with Conservative policies, “they don’t like us and they don’t trust our motives” he said.

In comments that will be seen by some as a direct challenge to David Cameron’s leadership, he suggested that Boris Johnson was the only politician in the party to understand this.

“We are already doing what I am suggesting. It just happens to be called Boris Johnson,” Boles said, adding that “he reaches those elements which have not been reached by the rest of us”.

Boles, who was previously in favour of a permanent coalition between the Conservatives and Liberal Democrats, said he now favoured forming a new “National Liberal party” instead.

The party would have the same relationship to the Conservatives as the Co-operative party has to Labour, with MPs standing on a joint ticket.

He suggested that it could be used to “recruit new supporters who might initially balk at the idea of calling themselves Conservative”.

Boles’ ideas were immediately dismissed by Downing Street yesterday. Asked if the prime minister still has confidence in his minister following his comments, a spokesperson replied “he does.”