The "chaotic" experience of Brexit "proves" Scottish independence would be even worse, the leader of the Scottish Liberal Democrats has claimed.

Willie Rennie told Scotland Tonight the Leave vote in the 2016 EU referendum showed the problems with "big-bang constitutional change".

He vowed that all Scottish Liberal Democrat MPs elected in the general election on December 12 will be focused on stopping both Brexit and independence.

Rennie refused to concede that Brexit had harmed the union, saying the case for Scotland staying in the UK remained "strong".

But he admitted that he "regrets" decisions made by the Lib Dems while in coalition government with the Conservatives at Westminster.

The party leader is the latest senior Scots politician to be interviewed on the programme by STV's political editor Colin Mackay as part of a series of election specials.

The Scottish Lib Dem manifesto sets out the party's opposition both to Britain leaving the EU and Scotland leaving the UK.

Asked if independence would be worse than Brexit, Rennie told STV: "I actually think it would be worse for Scotland.

"And that's saying something, because Brexit is chaotic and what really we need to recognise is that this constitutional change, this constitutional chaos needs to come to an end because it's not good for our country.

"It's dividing people, it's damaging the economy and it needs to stop."

He added: "Things have certainly changed, because Brexit's proven that independence would be a damn sight worse than what we ever thought it would be...

"Brexit proves that big-bang constitutional change is really difficult and it's causing so much economic damage, we should not repeat it."

Pressed on if an independent Scotland that remained in the EU would still be worse than Brexit, the Scottish Lib Dem leader answered: "I think there would be real challenges."

He went on: "The border issue that Nicola Sturgeon has already recognised as being an issue, that there may be a border between Scotland and England, that would cause tremendous difficulty.

"Remember, the trade with the rest of the UK is so much greater than the trade with Europe, so the challenges would be significant.

"Let's just put an end to all this... let's just stay in Europe and stay in the United Kingdom. That's the best solution."

Rennie said there was "no doubt" that Boris Johnson had done "an awful lot to damage the integrity of the United Kingdom".

But he said: "The case for the United Kingdom remains strong.

"The family of nations, the ties that we have, the economic cross-border trade is tremendously important.

"The fact that we've got soft power across the globe is incredibly important for Scotland and the rest of the United Kingdom."

Referring to the Prime Minister's Brexit deal, Rennie added: "It's just a shame you can't rely on the Conservatives to make that case because they are putting that border down the Irish Sea."

Quizzed on if his support for a second Brexit referendum but his opposition to a second independence vote is hypocrisy, the Lib Dem MSP said the cases were different.

Rennie said: "To be fair to the SNP, back in 2014, we did have a White Paper. It was a bit repetitive but it was 600 pages long, it had tremendous detail in it.

"We knew what we were voting for when we rejected it, that was clear. In 2016, we had two campaigns for Leave.

"They said contradictory things - sometimes very contradictory things - and then we had slogans on the side of a bus that actually turned out to be a pack of lies...

"Therefore, it would only be right now for people to be absolutely sure that they want to have that Brexit deal.

"If it's good enough for the country, they'll approve it. If it's not, they'll reject it."

On the Liberal Democrats' time in coalition government with the Tories, between 2010 and 2015, Rennie said subsequent Conservative governments had shown by contrast the positive influence his party had.

But asked about measures like the bedroom tax, universal credit, benefit caps and increasing tuition fees in England, he replied: "Every party that's in government makes mistakes."

He added: "Of course I regret some of the decisions that we were required to make...

"Those who were in government have made it clear where they got it wrong and they submitted apologies on those occasions.

"I wasn't there, so I'm not going to through those things but what I can tell you is it was not a one-way street.

"There were many things we managed to achieve, there were many things we held the Conservatives back on."