Opposition leaders attempted to outbid each other on Thursday night with their climate credentials in the first ever election debate focusing on the environmental emergency, in which the absent Boris Johnson was replaced by a melting ice sculpture.

In place of the prime minister, Channel 4 placed an ice sculpture, representing, they said, the emergency on planet Earth. A second ice sculpture took the place of Brexit party leader Nigel Farage, who also refused to take part.

The Conservatives accused the broadcaster of bias for not allowing Michael Gove to take Johnson’s place, accusing them of “conspiring” with Labour leader Jeremy Corbyn to block the party from making their case.

Gove had turned up to the studios but was turned away by Channel 4 who said the debate was for party leaders only. In a response designed to overshadow the programme, the Conservatives immediately complained to broadcasting regulator Ofcom and threatened to review its broadcasting licence.