The Conservative Party has complained to the UK's communications regulator, Ofcom, after an ice sculpture was used in place of Prime Minister Boris Johnson during a Channel 4 debate.

Party leaders faced questions about how they will tackle the issue of climate change during the televised Emergency On Planet Earth debate.

But after Mr Johnson did not attend, an ice sculpture of the world with "Conservatives" written on it was placed on his podium.

Brexit Party leader Nigel Farage also declined to attend and was replaced by a similar sculpture with his party logo.

A letter from the Conservatives, addressed to Ofcom Election Committee chairman Tim Suter, said it offered Channel 4 the former environment secretary Michael Gove to be the party's representative for the debate.

"Channel 4 News has refused to accept this representative, and stated that they intend to 'empty chair' the Conservative Party if the Prime Minister does not attend," the letter said.

"This effectively seeks to deprive the Conservative Party of any representation and attendance at the Channel 4 News debate.

"It has even been reported that Channel 4 has commissioned an ice sculpture of the Prime Minister to represent the Conservative Party.

"Were this the case, this would represent a significant breach of the Code through such a provocative partisan stunt, which would itself constitute making a political opinion in its own right."

A spokeswoman for Channel 4 News said ahead of the debate that Mr Gove "is not the party leader" when asked if he could replace Mr Johnson.

The letter, sent by Lee Cain, on behalf of the Conservative Party, claimed it "is part of a wider pattern of bias by Channel 4 in recent months.

"I would be grateful if Ofcom could consider this matter with due urgency.

"If Ofcom takes the view that this matter could not be considered until post-broadcast, I would request that this complaint is assessed subsequent to the broadcast, given the unfortunate precedents that Channel 4's actions may set."

It comes as a Conservative source told BuzzFeed News that if the party wins the coming election it will reassess Channel 4's public service broadcasting licence.

"If we are re-elected, we will have to review Channel 4's Public Services Broadcasting obligations," the source told BuzzFeed News.

"Any review would of course look at whether its remit should be better focused so it is serving the public in the best way possible."

Presenter Krishnan Guru-Murthy, thanking the leaders after the debate said: "Thank-you also to Michael Gove from the Conservative Party who did come here but sadly, as we made clear from the start, this debate was for leaders only and our leaders were only prepared to debate other leaders.

"Our offer to Boris Johnson and Nigel Farage to come here and discuss the climate emergency remains open."