THE UK Government should not block a second referendum by imposing a “fatwa” against Scottish independence, former deputy Prime Minister Nick Clegg has said.

The former Liberal Democrat leader also warned Theresa May’s slow methodical nature and “rigidity” could be a handicap for the Unionist side in a quick-moving independence campaign.

His comments echoed former Scottish Secretary Alistair Carmichael, who told the Herald he feared Mrs May would try to re-run the heavy-handed “Project Fear” approach of 2014.

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Nicola Sturgeon has said a second referendum is “all but inevitable” if the Prime Minister rejects her proposal for a bespoke Brexit deal keeping Scotland in the EU single market.

She has also said the autumn of 2018 would be a “common sense time” to hold a vote.

Talking to the media at the Scottish LibDem conference, Mr Clegg, who was in the Coalition in 2014, was asked if the UK Government should block another referendum by denying Holyrood the necessary legislative power under Section 30 of the 1998 Scotland Act.

He said: “I think it would be very difficult for any government of any composition in London to try and impose a fatwa on any move towards a referendum, if that was something which was being pushed, however unwelcome that is.

“Do we think the solution to a country careering towards hard Brexit is to have another divisive and all-absorbing referendum about whether the UK survives or not? No we don’t.”

It would not be legitimate for Westminster to frustrate the will of Scotland in the way the Spanish government had banned Catalonia from holding a referendum on autonomy, he said.

“Clearly, in a mature democracy, you can’t do that.”

Asked about Mrs May’s ability to fight a referendum, he said she was “thorough” and “methodical”, but that there was also “a certain rigidity”.

He said: “I don’t think she’d ever call herself a particularly agile, innovative politician. The weakness which may well manifest itself in both election campaigns and referenda campaigns is these are very fast moving events, in which you don’t control all the factors.”

Mr Clegg later told the conference there was an “almost umbilical link”' between the English nationalism of a hard Brexit Conservative Party and the “absolute fixation that the SNP have to push yet another referendum on independence here in Scotland”'.

He said: “They loathe each other but need each other. They are both political cousins and terrible twins. They are the ying and yang of British politics.”

The Nationalists were “invoking the rigid drive towards a hard Brexit by the Conservatives as their most proximate alibi” for a second referendum, he said.

He added: “At the moment we're in this kind of tailspin where the Conservative Party's hellbent determination on a hard Brexit is being supplemented and accompanied by the SNP's hellbent determination to deliver another referendum. They sort of feed off each other.

“The key challenge in British politics is to stop that tailspin before things get seriously out of hand and we see not only immense damage to the United Kingdom as a whole by a badly administered Brexit, but that we also end up in the process losing the family of nations in the United Kingdom to boot. That's something we want to fight on all fronts.''

However Scottish LibDem leader Willie Rennie will today accept a second referendum is coming and say his party should make the “emotional case” for the Union in the campaign.

READ MORE: Unspun: the political diary

He will tell activists: “I will stand up for our United Kingdom family. We will lead the way on the kind of campaign for the United Kingdom that we want to see.

“Britain is full of people who care. We should celebrate our generosity and compassion. No Scottish nationalist will tell me that I should be ashamed. I am proud of who we are.

“So as we head into another referendum the responsibility on liberals is great. We must stand up and be counted. This is a battle of ideas and values, not of identities and flags.”