Metro mayor Dan Norris says controversial images of him and his dog plastered on a double-decker, "unlawfully" paid for with £10,000 of taxpayers' cash, had to be so massive because "it's a big bus".

Legal and finance chiefs at the West of England Combined Authority (Weca) have ruled that the "bus wrap", which was intended to publicise the Birthday Bus scheme and driver shortage crisis, amounted to unjustifiable political self-promotion.

Weca boss Richard Ennis pulled the bus from public view when he found out and raised concerns that the stunt may have broken local government rules.

But Labour mayor Mr Norris, who denies any wrongdoing, says the images had to be as large as three metres tall because people would otherwise not have been able to see them.

It comes as a date has been announced to reconvene an emergency meeting of the Weca committee where the leaders of the three councils that make up the combined authority will decide if they agree the stunt was illegal and if there should be any punishment.

That should have happened on Friday, December 1, but only the leaders of South Glos and Banes showed up, with Bristol city Labour mayor Marvin Rees away at COP28 in Dubai and for the first time ever not sending a deputy to a Weca committee, which is understood to be because they disagree that the meeting should legally go ahead.

Asked about the fiasco on BBC1 Politics West, Mr Norris initially said that although he had lots to say, he was not allowed to because he could not be seen to be influencing any decision.

But challenged by host David Garmston about the size of the photos of him and his dog Angel, the West of England mayor said: "Well what can I say?

"It's a big bus. You know, if you put it any smaller, you wouldn't see it. It's a huge bus.

"This was the Birthday Bus scheme, which I encourage people to take up, but also to recruit bus drivers because we've seen a lot of bus cuts lately and that's because largely there has been a shortage of bus drivers, so it's hugely important to keep recruiting.

"We've been successful but we need to be better yet. So this is about those very important messages."

Mr Garmston said: "But people are saying that wasn't really about promoting bus travel, it was about promoting Dan Norris."

The mayor replied: "Well, people might say that. You're trying to draw me in and I've told you I can't, unfortunately. But I'll have plenty to say when I'm allowed to."

Mr Norris has previously defended the bus wrap and said metro mayors are supposed to be "visible".

An extraordinary meeting of the Weca committee will take place at 7.30pm on Tuesday, December 12, at the organisation's headquarters in Redcliffe, Bristol.

If he attends, the mayor will have to declare a non-pecuniary interest and leave the room during the debate.

A report to the committee said: "The bus wrap is reminiscent of political campaign buses which exist to serve the explicit purpose of seeking to influence voters."

It said an external review found officers under direct instruction by Mr Norris "did not consider the need to check or discuss this with anyone within the combined authority, nor did they consider the need to follow the combined authority's expected control processes".